LIBRARY OF CONGRESS. 



Shelf. •:S"..5.2. ^- . 

/ \ ^ * T 



UNITED STATES OF AMERICA. 



I 



HORSES^ TEETH: 



A TREATISE ON THEIR 



MODE OP DEVELOPMENT, ANATOMY, 
MICROSCOPY, PATHOLOGY, AND DENTISTRY ; COMPARED WITH 
THE TEETH OP MANY OTHER LAND AND MARINE 
ANIMALS, BOTH LIVING AND EXTINCT ; 
WITH A VOCABULARY AND COPI- 
OUS EXTRACTS PROM 
THE WORKS OP 



ODONTOLOGISTS AND VETERINARIANS. 



U^ 



WILLIAM H. CLARKE. 



SECOND EDITION, REVISED. 




Horses have very nearly the same diseases as men.— P^iny. 
We out?ht to make not merely books, but valuable collections, and to 
acknowledge the sources whence we derive assistance.— /Jic?. 



NEW YORK : ' OCJ 1 8 '890 

WILLIAM R. JENKINS, V ,-^^6 4 g" 



veterinary publisher and bookseller, 
• 850 Sixth Avenue 
1884. 






Copyright, 1S79, by William H. Clarke. 



Smith & McDougal, Elkctrotypkks, 
82 BeekPinn St., N, Y. 



PREFACE 



THE favorable reception of the first edition of this 
work by both press and piibhc and my desire 
to encourage the study of Veterinary Science and 
Comparative Anatomy are the chief reasons for a 
Revised Edition. The improvements consist in an 
Appendix, numerous Ilhistrations, a new Index, and 
the correction of errors in and the addition of fresh 
matter to the text and vocabulary. 

I am indebted to Mr. Jacob L. Wortman of Phil- 
adelphia for the able article on fossil horses in the 
Appendix, and to Prof. E. D. Cope, editor of Tlie 
American Naturalist, for a careful revision and im- 
provement of it. Some of the reference notes, how- 
ever, are my own. 

It was not my intention originally to make the book 
an exponent of the Doctrine of Evolution. The dis- 
cussion of the subject, however, is justifiable, for a 
work that does not embrace all the facts science 
furnishes is unworthy of the age, and to shirk the re- 
sponsibility of the discussion because the subject is 
unpopular is cowardly. The fact, that fossil horses' 
teeth are inseparably connected with those of the 
modern horse renders their consideration unavoidable. 
Further, in addition to being one of the most impor- 
tant factors Paleontology has thus far furnished in 



IV PREFACE. 

elucidating the subject of Evolution, they give in- 
creased scope and importance to the book itself. 
Truly the late Dr. John W. Draper was right when, 
at a mere glance, he said : ^' The subject (horses' 
teeth) is so suggestive !" 

So far as Evolution is concerned, I can only repeat 
what I said in the first Preface, namely, that it denotes 
improvement, and that Nature's laws are immutable, 
and to oppose them is as foolish as to beat the head 
against a stone wall. 

Again, as said in the first Preface, I think I can say 
now from experience that Special Works, on account 
of the thoroughness with which they are usually pre- 
pared, are growing in public favor (an opinion in 
which so able a journal as The Syracuse (N. Y.) 
Standard concurs), and that while General Works 
have their advantages, thoroughness of detail is not 

usually among them. 

W. H. 0. 

New York, September, 1883. 



CONTENTS 



INTRODUCTION— Fundamental Principles of Dental Science 7 

CHAPTER I. 

TOOTH-GERMS (ODONTOGENY). 



Periods at which the Germs are vi^^ible injthe Fetus.— Dentine and 
Enamel Genns.- 
Gi 

Four 
itot's Researches. 



uus uL \Min;u iiil; ^^clUJr^ aiu viMuiu lu liiu rtjius. — ucniine ana 
Enamel Germs.— A Cciuciit Germ in t!ie Foal. — The Horde's Upper 
Grinders said to be developed from Five Germs, the Lower from 
Four.— Similar development of the Human Teeth.- Monsieur Ma^- 



CHAPTER IT. 

THE TEMPORARY DENTITION. 
Twelve Incisors and Twelve Molars.— Whv the Incisors are calle 
"Nippers."— The Treatment of Foals 'Aflects Teethin^. -Roots 
of Milk Tueth Absorbed by the Permanent.— The Tushes.' 47 

CHAPTER III. 

THE PERMANENT DENTITION. 
Distinction between Premolars and Molars.— The Bow-like Incisors.— 
Contrasts between the U])per and Lower Grinders, ;ind the Rows 
formed by them. -The Incisors saved from Friction.— Horses' 
Teeth compared with those of other Animals.— Measurements.— 
Time's Changes.— Growth during Life 53 

CHAPTER IV. 

THE CANINE TEETH OR TCSHES. 

Practically Useless.— Different in their Nature from the other Teeth.— 
Were they formerly Weapons of Ofleuir^e and Defense)— Views of 
Messrs. Darwin. Hunter. Bell, Yonaft, and Winter.— Their time of 
Cutting the most Critical Period of the Horse's Life 75 

CHAPTER V. 

THE REMNANT TEETH. 

Usually regarded as Phenomenons.— The Name.— Traced to the Fossil 
Horses, in which (in the Pliocene Period) thev ''Cea-^ed to be Func- 
tionally Devclop"d.'*— X.itnre's Metamorphoses -•' The AL^encies 
which are at work in Modeling Animal and Ve£retab]e Forms."— 
Why Remnafit Teeth are often as it were. Prematurely Lost.— Fos- 
sil Horses and a Fossil Toothed-Bird 94 



VI CONTENTS. 

CHAPTER VI. 
DENTAL CYSTS AND SUPERNUMERAKY TEETH. page 

Teeth growius in various parts of the Body. — Some Cysts more Prolific 
than others, Prodiiciiij? a Sccoud, if not a Third, " Dentition. ■"— 
Keports and Theories of Scienlilic Men.— Cases of Third Dentition 
iu Human Beings 115 

CHAPTER Vn. 

horses' TEETH UNDER THE MICROSCOPE. 

The Dentinal Tabes, Enamel Fibers, and Cemental Canals Described 
and Contrasted 130 

CHAPTER Vni. 

THE PATHOLOGY OF THE TEETH, 

Importanc3 of the Sitbject. —Caries caused by Inflamed Pulps, Blows, 
Virus, and Morbid Diathesis.— Supernumerary Teeth and other 
Derangements.— Tre|/hinuig the Sinuses.- Gutta Percha as a Fin- 
ing. — (.'leaning the Teeth.— A Diseased Fossil Tooth 136 

CHAPTER IX. 

THE DENTISTRY OF THE TEETH. 

Reports of Cases Treated by Various Surgeons.— Gutta Percha as a 
Filling for Trephined Sinujcs.- Teeth Pressing against the Palate. 
-Passing a Probe through a Decayed Tooth.— Death of a Horse 
from Swallowing a Diseased Tooth 175 

CHAPTER X. 

FRACTURED JAWS. 

How Caused, and how to Distinguish an Abrasion of the Gums from a 
Fracture of the Bone.— Replacing an Eye, Amputating part of a 
Lower Jaw, taking a Fractured Tooth and Bones out through the 
Nostril, &c 194 

CHAPTER XI. 

THE TEETH AS INDICATORS OF AGE. 
Their various ways of Indicating Age.— The " Mark's " Twofold Use.— 
The Dentinal Star.— Marks with too much Cement.— Tricks of the 
Trade.- Crib-biting.— Signs of Age Independent of the Teeth 203 

CHAPTER XII. 

THE TRIGEMINUS OR FIFTH PAIR OF NERVES. 

Its Nature and the Relation it bears to the Teeth.— Its Course in the 
Horse and in Man 216 

VOCABULARY 227 

APPENDIX.— Recent Discoveries of Fossil Horses.— Views of an Evo- 
luMonist.— Original Home of the Horse.— Elephant Tooth-Germs.— 
Filling Children's Teeth 257 

INDEX 279 

PUBLIC OPINION 287 



IXTRODUCTIOX 



The following matter, which is designed to give at 
least a synopsis of the fundamental principles of dental 
science, is compiled from the works of the best known 
odontologists. It is somewljat heterogeneous in its 
make-up, and is, moreover, considering that it is an 
Introduction to a special work, anomalous, being 
rather an adjunct to than an explanation of the work 
itself. Its lack of coherency and the few repetitions, 
the inevitable concomitants of all compilations, are 
offset by the interest of its historical records and the 
scope and clearness of its thoughts and deductions. 
While it does not treat specially of horses' teeth, it is 
just as applicable to them as to human teeth, or to 
those of any of the other animals mentioned. It is 
believed that the student of dental science will find 
the matter as useful as it is interesting. 

In his work entitled "The Anatomy of Vertebrates" 
(vol. i, pp. 357-8), Prof. Richard Owen says: 

"A tooth is a hard body attached to the mouth or 
beginning of the alimentary canal, partially exposed, 
when developed. Calcified teeth are peculiar to the 
vertebrates,, and may be defined as bodies primarily, if 
not permanently, distinct from the skeleton, consisting 



Vm IXTHODUCTIOK^. 

of a cellular and tubular basis of minimal matter, con- 
taining earthy particles, a fluid, and a vascular pulp. 

^^In general, the earth is present in such quautity 
as to render the tooth harder than bone, in which case 
the animal basis is gelatinous, as in other hard parts 
where a great proportion of earth is combined with 
animal matter. In a very few instances, among the 
vertebrate animals, the hardening material exists in a 
much smaller proportion, and the animal basis is albu- 
minous ; the teeth here agree, in both chemical and 
physical qualities, with bone. 

^•'I propose to call the substance which forms the 
main part of all teeth dentine.* The second tissue, 
which is the most exterior in situation, is the cement. 
The third tissue, which, when present, is situated be- 
tween the dentine and cement, is the enamel. 

"Dentine consists of an organized animal basis and 
of earthy particles. The basis is disposed in the form 

* In a reference note in the Introduction to liis " Odontogra- 
phy," Prof. Owen says: "Besides the advantage of a substan- 
tive for an unquestionably distinct tissue under all its modifica- 
tions in the animal kingdom, the term dentine may be inflected 
adjectively, and the properties of this tissue described without 
the necessity of periphrasis. Thus we may speak of the ' denti- 
nal ' pulp. ' dentinal ' tubes or cells, as distinct from the corre- 
sponding properties of the other constituents of a tooth. The 
term 'dental' will retain its ordinary sense, as relating to the 
entire tooth or system of teeth." 

Note. — The particular paragraph to which the above note re- 
fers is from Prof. Owen's " Odontograpliy." " The Anatomy of 
Vertebrates " having been written about twenty-five vears sub- 
sequent to the " Odontog-ranhy," and therefore reflecting the 
Professor's riper thoughts, the extracts made from it were sub- 
stituted for very similar matter in the " Odontography." 



TL'BES WITH XOURISIIIXG, COI^OKLESS TLUID. ix 

of compartments or cells, and extremely minute tubes. 
The earthy particles have a twofold arrangement, be- 
ing either blended with the animal matter of the in- 
terspaces and parietes of the tubes, or contained in a 
minute granular state in their cavities. The density 
of the dentine arises principally from the proportion 
of earth in the first of these states of combination. 
The tubes contain, near the formative pulp, filament- 
ary processes of that part, and convey a colorless fluid, 
probably transuded * plasma.' They thus relate not 
only to the mechanical conditions of the tooth, but to 
the vitality and nutrition of the dentine. This tissue 
has few or no canals large enough to admit capillary 
vessels with the red particles of blood, and it has been 
therefore called 'unvascular dentine.' 

" Cement always closely corresponds in texture with 
the osseous tissue of the same animal ; and whenever 
it occurs of diff'erent thickness, as upon the teeth of 
the horse, sloth, or ruminant, it is also traversed, like 
bone, by vascular canals. When the osseous tissue is 
excavated, as in dentigerous vertebrates above fishes, 
by minute radiated cells, forming, with their contents, 
the ' corpuscles of Purkinje,' these are likewise present, 
of similar size and form, in the cement, and are its 
chief characteristic as a constituent of the tooth. The 
hardening material of the cement is partly segregated 
and combined with the parietes of the radiated cells 
and canals, and is partly contained in disgregatcd 
granules in the cells, wliich are thus rendered white 
and opaque, viewed by reflected light. The relative 
density of the dentine and cement varies according to 
the proportion of the earthy material, and chiefly of 
that part which is combined with the animal matter 
in the walls of the cavities, as compared with the size 



X IXlllODUCTIOX. 

and number of the cavities themselves. In the complex 
grinders of the elephant, the masked boar, and the 
copybara, the cement, which forms nearly half the 
mass of the tooth, wears down sooner than the dentine. 
" The enamel is the hardest constituent of a tooth, 
and, consequently, the hardest of animal tissues; but 
it consists, like the other den ;:al substances, of earthy 
matter arran.s^ed by organic forces in an animal matrix. 
Here, however, the earth is mainly contained in the 
canals of the animal membrane, and, in mammals and 
reptiles, completely fills those canals, which are com- 
paratively wide, whilst their parietes are of extreme 
tenuity. The hardening salts of the enamel are not 
only present in far greater proportion than in the den- 
tine and cement, but, in some animals, are peculiarly 
distinguished by the presence of the fluate of lime." 

Again Prof. Owen says ("Anat. of Vert." vol. i, pp. 
359-GO) : 

'^ Teeth vary in number, size, form, structure, modi- 
fications of tissue, position, and mode of attachment 
in different animals. They are principally adapted for 
seizing, tearing, dividing, pounding, or grinding the 
food. In some animals they are modified to serve as 
weapons of offense and defense ; in others, as aids in 
locomotion, means of anchorage, instruments for up- 
rooting or cutting down trees, or for transport and 
working of building materials. They are characteristic 
of age and sex, and in man they have secondary rela- 
tions subservient to beauty and to speech. 

"Teeth are always most intimately related to the 
food and habits of the animal, and are therefore highly 



tOST DUKABLE OF a::imal SULST.'.XCES. xi 

interesting to the ph3'siologist. They form for the 
same reason most- important guides for tlie naturalist 
in the classitication of animals; and their value, as 
zoological characters, is enhanced by the facility with 
which, from tlieir position, they cau be examined in 
living or recent animals. The durability of their tis- 
sues renders them not less available to the paleontolo- 
gist in the determination of the nature and affinities 
of extinct species, of whoso organization they are often 
the sole remains discoverable in the deposits of former 
periods of the earth's history." 

Prof. A. Chauveau says (" Comparative Anatomy of 

the Domesticated iVnimals"): 

'• Identical in all our domesticated animals by their 
general disposition, mode of development, and struc- 
ture, in their external conformation tlie teeth present 
notable differences, the study of which offers the 
greatest interest to the naturalist. For it is on the 
form of its teeth that an animal depends for its mode 
of alimentation; it is the regime, in its turn, which 
dominates the instincts, and commands the diverse 
modifications in the apparatus of the economy ; and 
there results from this law of harmony so striking a 
correlation ])etween the arrangement of the teeth and 
the conformation of the other organs, that an anato- 
mist may truly say, 'Give me the tooth of an animal, 
and I will tell you its habits and structure.'" 

In a letter which I wrote to Prof. Theodore Gill, of 
the Smithsonian Institution, Washington, D. C, I 
asked what there was about teeth that enabled natu- 
ralists to tell so much by them. In reply he said: 



XU li^TRODUCTIOX. 

" The teeth are quite constant in the same type, are 
generally appreciably modified according to family, are 
the most readily preserved in a fossil state, and are in 
direct relation with the economy of the animal.^ Hence 
they furnish the best indications of the relations of 
the animal to w^hich they belonged, especially in cases 
where the type was not very different from an existing 
one. In the case of the older and more aberrant types, 
hov/ever, the indications furnished by the dentition 
should be accepted with great caution." 

In the Introduction to his '^ Odontography " Prof. 
Owen gives, besides his own and other men's views, a 
history "of the leading steps to the present knowl- 
edge" of dental science (that is, up to 1844), of which 
the following are extracts : 

" As regards the teeth, the principle of chief import 
to the physiologist arises out of the fact, which has 
been established by microscopic investigations, that the 
earthy particles of dentine are not confusedly blended 
with the animal basis, and the substance arranged in 
superimposed layers, but that these particles are built 
up with the animal basis as a cement, in the form of 
tubes or hollow columns, in the predetermined arrange- 
ment of which there may be discerned the same rela- 
tion to the acquisition of strength and power of resist- 
ance in the due direction, as in the disposition of the 
columns and beams of a work of human architecture. 

" Whoever attentively observes a polished section or 
a fractured surface of a human tooth may learn, even 
with the naked eye, that the silky and iridescent luster 
reflected from it in certain directions is due to the 
presence of a fine fibrous structure. 



EARLY illCROSCOPICAL mSCOVERIES. Xlll 

" Malpighi,* in whose works may be detected the 
germs of niany important anatomical truths that have 
subsequently been matured and estabhshed, says the 
teeth consist of two parts, of which the internal bony 
layers (dentine) seem to be composed of librous and, as 
it were, tendinous capillaments reticularly interwoven. 

" Leeuwenhoek,f having applied his microscopical 
observations to the structure of tiie teeth, discovered 
that the apparent fibers were really tubes, and lie com- 
municated a brief but succinct account of his discovery 
to the Royal Society of London, which was published, 
together with a figure of the tubes, in No. 140 of their 
Transactions. This figure of the dentinal tubes, with 
additional observations, again appeared in the Latin 
edition of Leeuwenhoek's works, published at Leyden 
in 1730.- The dentine of the human teeth, and also 
that of young hogs, is described as being * formed of 
tubuli spreading from the cavity in the center to the 
circumference/ He computed that he saw a hundred 
and twenty of the tubuli within the forty-fifth part of 
an inch. He was aware also of the peculiar substance 
now termed the cement, or crnsta j)etrosa, which enters 
mto the composition of the teeth of the horse and the 
ox. 

"These discoveries may be said to have appeared 
before their time. The contemporaries of Leeuwen- 

* An Italian physician ; born in 1628 ; died in 1604. He was 
tlie first to apply the newly-invented microscope in the study of 
anatomy. 

X A Dutch naturalist and manufacturer of optical instruments. 
His microscopes were said to be the best in Europe. Besides 
his dental discoveries, he discovered the red g-lol)ules of the 
blood, the inkisorial animaVules, and that of the spermatozoa. 
Born in Delft October 24, 1632; died there Aumist 26, 1723. 



XIV livTRODUCTiUN. 

hoek were not prepared to appreciate them ; besides 
they could neither re^jeat nor contlrm them, for his 
means of observation were pecuHarly his own; and 
hence it has happened that, with the exception of the 
learned Portal,* they have either escaped notice, or 
have been designedly rejected by all anatomists until 
the time of the confirmation of their exactness and 
truth by Purkmje in 1835." 

Continuing tlie subject, Prof. Owen further says of 
the three constituent parts of teeth — dentine, enamel, 
and cement — beginning with 

THE DESTINE. 

"Purkinje states that the dentine consists, not of 
superimposed layers, but of fibers arranged in a homo- 
geneous intermediate tissue, parallel with one another, 
and perpendicular to the surface of the tooth, running 
in a somewhat wavy course from the internal to the 
external surface, and he believed these fibers to be 
really tubular, because on bringing ink into contact 
with them, it was drawn in as if by capillary attraction. 

" On the publication of this discovery, it was imme- 
diately put to the test by Prof. Miiller, by whom the 
tubular structure of the denthie was not only con- 
firmed, but the nature and one of the offices of the 
tubes were determined. He observed that the white 
color of a tooth was confined to these tubes, which were 
imbedded in a semi transparent substance, and he found 
that the whiteness and opacity of the tubes were re- 
moved by acids. On breaking a thin lamella of a tooth 
transversely with regard to its fibers, and examining 
the edge of the fracture, Miiller perceived tubes pro- 

* " Histoire de rAnatomie et de la Chirurgie," Paris, 1770. 



WHAT TiTE Trr;r.s contain. xv 

jx^cting here and there from the surfaces. They were 
white unci opaque,, stiff, straight, and apparently not 
flexible. This appearance is well repres.-nted in the 
old figure by Leeuwenhook. If the lamellae had been 
previously acted upon by acid, the projecting tubes 
were flexible and transparent, and often very long. 
Hence Miiller inferred that the tubes have distinct 
walls, consisting of an animal tissue, and tiiat, besides 
containing earthy matter in their interior, their tissue 
is, in the natural state, impregnated with calcareous 
salts."* 

THE CEMENT. 

" The organized structure and microscopic character 
of the cement were first determined by Purkiuje and 
Faenkcl, and the acquisition of these facts led to the 
detection of the tissue in the simple teeth of man and 
carnivorous animals. The cement is most conspicuous 
where it invests the root of the tooth, and increases m 
thickness as it approaches the apex of the root. The 
animal constituent of this part of the cement bad been 
recognized by Berzelius as a distinct investment of the 
dentine long before the tissue of which it formed the 
basis was clearly recognized in simple teeth. Berzelius 
describes the cemental membrane as being less consist- 
ent than the animal basis of the dentine, but resisting 

" If Lord Bacon's theory is correct, the probability is that these 
tubes contain something besides earthy matter and calcareous 
salts, to wit, spirit. In "Novum Organura" he says (B. Mon- 
tagu, vol. xiv, p. 417): "All things abhor a solution of their 
continuity, but yet in proportion to their rarity. The more rare 
the bodies be, the more they suffv^r themselves to be thrust into 
small and narrow iiassaffos ; for water will go into a passage 
which dust will not go into, air which >vater will not go into, 
and flame and spirit which air will not go into." 



XVI IKTKODUCTIOX. 

longer the solvent action of boiling water, and retain- 
ing some fine particles of the eartliy phosphates when 
all such earth had been extracted from the dentinal 
tissue. Cuvier also states that the cement is dissolved 
with more difficulty in acid than the other dental tis- 
sues. Retzius,'^ however, states that the earth is 
sooner extracted by acid from the cement than from 
the dentine of the teeth of tiie horse. 

"In recent mammalian cement the radiated cells, like 
the dentinal tubes, owe their whiteness and opacity to 
the earth which they contain. According to Retzius, 
'numerous tubes radiate from the cells, wiiich, being 
dilated at their point of beginning, give the cells the 
appearance of an irregular star. These tubes form 
numerous combinations with each other, partly direct 
and partly by means of fine branches of y^^oot^^ ^^ 
-g-o^y-Q-th of an inch in diameter. The cells vary in 
size. The average size of the Purkinjean cells in hu- 
man cement is y-gVo^h of an inch. In sections made 
transversely to the axis of the tooth, it is clearly seen 
that these cells are arranged in parallel or concentric 
strise, of which some are more clearly and others more 
faintly visible, as if the cement were deposited in fine 
and coherent layers.' The layer of cement is found in 

*Prof. Retzius, of the University of Stockholm, informs us 
that he had been led by the iridescence of the fractured surface 
of the substance of a tooth to conceive that that appearance was 
due, as in the crystalline lens, to a fine fibrous structure, and that 
he communicated his opinions as to the re,o-ular arranofement of 
these fibers to some of his colleagues in 1834. In 1885, havintr 
obtained a powerful microscope, he began a series of more exact 
researches on the intimate structure of the teeth in man and 
the lower animals, which he communicated to the Royal Acad- 
emy of Sciences at Stockholm on January 13, 1838, being then 
unacquainted with the discoveries of Purkinje, — Owen. 



EXOSTOSIS OF THE ROOT. xvii 

the deciduous teeth, but is relatively thinner, and the 
Purkiujean cells are more irregular. 

■*'^In growing teeth, with roots not fully formed, 
the cement is so thin that the Purkinjeau cells are 
not visible. It looks like a fine membrane, and has 
been described as the periosteum of the roots, which 
are wholly composed of it ; but it increases in thick- 
ness with the age of the tooth, and is the seat and ori- 
gin of what are called exostoses of the roots/ These 
growths ai-e subject to the formation of abscesses, and 
all the morbid actions of true bone. 

"It is the presence of this osseous substance which 
renders intelligible many well-known experiments of 
which human teeth have been the subjects, such as 
tlieir transplantation and adhesion into the combs of 
cocks, and the establishment of a vascular connection 
between the tooth and the comb. 

"Under every moditication the cement is the most 
highly organized and most vascular of the dental tis- 
sues, and its chief use is to form the bond of vital 
union between the denser and commonly un vascular 
constituents of the tooth and. the bone in which the 
tooth is implanted. In u few reptiles (now extinct), 
and in the herbivorous mammalia, the cement not only 
invests the exterior of the teeth, but penetrates their 
substance in vertical folds, varying in number, form, 
extent, thickness, and degree of complexity, aiid con- 
tributing to maintain that inequality of the grinding 
surface of the tooth whicli is essential to its function 
as an instrument for the comminution of vegetable 
substances.'** 

* Ce^iext Mistaken for Tartar (Odo^'tot/ithos\— Sur- 
geon E. Mayltcw pays (" The Horse's Month," &c.): "Within 
the alveolar cavity, the crusta fetrosa^ which becames of coa- 



XVm INTRODUCTION^. 



THE ENAMEL. 

"The higher an animal is placed in the scale of or- 
ganization, the more distinct and characteristic are not 
only the various organs of the body, but the different 
tissues which enter into their composition. This la\v 
is well exemplified in the teeth, although in the com- 
parison of these organs we are necessarily limited to 
the range of a single primary group of animals. We 
have seen, for example, that the dentine is scarcely, 
distinguishable from the tissue of the skeleton in the 
majority of fishes; but that its peculiarly dense, un- 
vascular, and resisting structure, Avhich is the excep- 
tionable condition in fishes, is its prevalent character 
in the teeth of the higher vertebrates. 

"So likewise with the enamel. This substance, 
whicli under all its conditions bears a close analogy 
with the dentine, is hardly distinguishable from that 
tissue in the teeth of many fishes. The fine calciger- 
ous* tubes are present in both substances, and undergo 
similar subdivisions, the directions only of the trunks 

siderable tliickness around tlie root, is of a yellowisli-wliite 
color ; but where, as ou the crown of tlie tooth, it is exposed to 
the chemical action of food and air, it presents a darker aspect, 
and resembles an accumulation of tartar, for which indeed it 
has been mistaken. It fills up the infundibula of the grinders 
and lines those of the incisors. It is pierced by all the vessels 
which nourish the" teeth." 

The editor of "The Veterinarian" (1849), in a "review" of 
Mr. Mayhew's work, says: "Both English and French veteri- 
nary writers have mistaken the crusta petrosa for tartar, not be- 
ing aware of its existence inside as well as outside of the tooth." 

* This word is peculiar to if not originated by Prof Owen. It 
is synonymous with the word Calciferous (limy). 



THE EXAMEL'.; VARIEGATED BEAUTIES. XIX 

and branches being reversed, agreeably with the con- 
trary course of their respective developments. The 
proportion of animal matter is also greater in tlie 
enamel of the teeth of fishes than in the higher verte- 
brata, and the proportion of the calcareous salts incor- 
porated with the animal constituent of the walls of 
the tubes is greater as compared with the suberystal- 
line part deposited in the tubular cavities. 

"The enamel may be distinguished, independently 
of its microscopic and structural characters, by its 
glistening, subtransparent substance, which is white 
or bluisli-white by reflected light, but of a gray-brown 
color when viewed, under the microscope, by trans- 
mitted light. * * * The enamel of the molar 
tooth of a calf, which has just begun to appear above 
the gum, and which can readily be detached from the 
dentine, especially near the beginning of the roots, is 
resolvable into apparently fine prismatic fibers. If 
these fibers be separately treated with dilute muriatic 
acid, and the residue examined with a moderate mao-- 
nifving power, in distilled water, or, better, in dilute 
alcohol, portions of more or less perfect membranous 
sheaths or tubes will be discerned, which inclosed the 
earthy matter of the minute prism, and served as the 
mold in which it was deposited. 

'•' Prof. Retzius, who obtained a small portion of *^ 
organic or animal substance from the enamel-fibers of 
an incompletely-formed tooth of a horse, conjectured 
that it was a deposition of that fluid which originally 
surrounds the loose enamel-fibers, and that *in pro- 
portion as these fibers are pressed tighter together, and 
additional fibers are wedged between them, the organic 
deposition js forced away.' 

*' Retzius accuratelv describes the enamel-fibers of 



XX INTRODUCTION. 

the horse as presenting the form of angular needles, 
about ^eVo^l^ of an inch in diameter, wliich are trav- 
ersed by minute and close-set transverse striae over 
the whole or a part of the fiber; and he conjectures 
that if the enamel-fiber be a mass of the calcareous 
salts, surrounded by an organic capsule, that the stride 
may then belong to the capsule, and not to the enamel- 
fiber. The later researches of Dr. Schwann add to the 
probability of this conjecture; and the absence of the 
minute striae in the enamel of fossil mammalian teeth, 
at least in the examples which I have submitted to 
microscopic investigation, may depend upon the de- 
struction of the original organic constituent of the 
enamel. 

'^The enamel-fibers are directed at nearly right 
angles to the surface of the dentine, and their central 
or inner extremities rest in slight but regular depres- 
sions on the periphery of the coronal dentine. Thus 
in the human tooth, the fibers which constitute the 
masticating surface are perpendicular, or nearly so, to 
that surface, while those at the lower part of the crown 
are transverse, and consequently have a position best 
adapted for resisting the pressure of the contiguous 
teeth, and for meeting the direction in which external 
forces are most likely to impinge upon the exposed 
crown of the tooth. The strength of the enamel-fibers 
is further increased by the graceful, wavy curves in 
which they are disposed. These curves are in some 
places parallel, in others opposed. Their concavities 
are commonly turned toward each other, where the 
shorter fibers, which do not reach the exterior of the 
enamel, abut by their gradually attenuated peripheral 
extremities upon the longer fibers. Other shorter fibers 
extend from the out?r surface of the enamel tov/ard 



EXAMEL LINES EARALLIX AXD WAVY. XXI 

the dentine, and are wedged into the interspaces of 
the longer fibers. In the teeth of fishes, tlie calciger- 
ous tubes or fibers of tlie enamel, which ramify and 
subdivide like those of the dentine, have their trunks 
turned in the opposite direction, or toward the periph- 
ery of the tooth. So likewise in human teeth the 
analogous condition may be diicerned in the slightly 
augmented diameter of the enamel-fibers at their pe- 
ripheral as compared with their central extremities. 
When the extremities of the human enamel-fibers are 
examined with a magnifying power of 300 linear 
dimensions, by reflected light, they are seen to be co- 
adapted, like the cells of a honey-comb, and, like these, 
to be, for the most part, hexagonal. 

"The internal surface of the enamel is marked by 
fine transverse lines or ridges, of which Retzius counted 
twenty-four in tlie vertical extent of one-tenth of an 
English inch of the crown of a human incisor. These 
lines are parallel and wavy, and, like the analogous 
markings on the surface of shells, indicate the succes- 
sive formation of the belts of enamel-fibers that encircle 
the crown of the tooth. They may be traced around 
the Avhole crown, but are very faint upon its inner or 
posterior surface. Retzius cites Loeuwenhoek as the 
discoverer of these superficial transverse lines of the 
enamel, but the older observer supposed them to be 
indicative of the intervals between the successive move- 
ments in the cutting of the tooth through the gum. 

"The enamel, by virtue of its physical qualities of 
density and durability, forms the chief mechanical 
defense of the tooth, and is consequently limited in 
most simple teeth to tlie exterior surface of the exposed 
portion of tlje dentine, forming the crown of the tooth. 
* * * In the herbivorous mammalia, with the 



xxii introductio:j5". 

exception of the Edentata, vertical folds or processes 
of the enamel are continued into the substance of the 
tooth, varying iu number, form, extent, and direction, 
and producing, by their superior density and resistance, 
the ridged inequalities of the grinding surface on which 
its efficacy in the trituration of vegetable substances 
depends." 

Dr. Boon Hayes's thoughts are thus recorded in a 
*' Medical Circular," extracts from which appear in 
"The Veterinarian" for 1853 (pp. 535-6): 

"In the first place, observe the pulpal cavity, which 
is to the tooth what the medullary cavity is to bone. 
Both originate in the same way. Into it passes an 
artery, a vein, and a nerve. These ramify upon the 
pulpal surface, the artery carrying blood to the denti- 
nal tubuli, whence the liquor sanguinis (not blood 
corpuscles) proceeds to the nourishment of this ap- 
parently inorganic mass. 

"In the teeth of some animals this cavity seems to 
send off diverticula between the dentinal tubuli, as if 
for the purpose of supplying them with more vascu- 
larity. The dentinal tubes open on the walls of the 
pulpal cavity, and thence radiate to the enamel supe- 
riorly and the crusta petrosa inferiorly. I think it 
would not be difficult to prove that caries of the teeth 
more frequently proceeds from inflammation begin- 
ning in this cavity than from any other cause. 

"When the tubes of the dentine are examined with a 
high magnifying power, and by transmitted light, they 
appear dark. They are much more minute in diameter 
than the blood globules; hence the liquor sanguinis 
alone can penetrate them for their nourishment; so 



pPtiMAUY a2;d secoxdary curves. ax;u 

that the teeth are in the same condition as bone in this 
respect. 

"The dentinal tnbss, as before said, appear dark; 
the Hghter and apparently broader masses are the real 
substance ol' the dentine. In this, and es})ecially near 
the layer closest to the enamel, dentinal cells are some- 
times seen, which may probably be analogous to the 
lacunae of bone. 

"If the dentinal curvatures are examined, it will be 
seen that they are of two kinds. One set is in bold 
and evident curves; the other is not so evident, but it 
exists, nevertheless, and a little patience and a high 
magnifying power will demonstrate the fact that its 
curves are ujyon the curves of the first set. The former 
are called the primarv, the latter the secondary curves 
of the dentinal tubuli (in botanical description, a 
biserrated leaf). From the tubuli minute bracelets 
are given off on the sides, and toward the end the tubes 
terminate, either in cells, by anastomosis, or by looping 
back upon themselves. 

"The cement at first envelops the whole tooth, but 
soon wears off the crown and as far down as the neck. 
Compared with the dentine and enamel, it is very soft, 
and more closely resembles bone ; in fact in some ani- 
mals it is continuous with the bone of the jaw, thus 
proving its identity. It contains lacunae and canalic- 
uli, and, when there is a large mass of it, something 
like Haversian canals. 

" There is a great analogy between tooth and bone. 
In the cement there is absolute likeness, and in the 
dentine analogies too striking to be overlooked, viz., 
the tubuli, analogous to the canaliculi, the intertubular 
cells, analogous to the lacunas, and the intertubular 
substance, analogous to the laminae of bone. In the 



XXIV INTRaDUCTIO]^. 

enamel the greatest departure is observablej but not 
wider than its peculiar function suggests; and it must 
be remembered, first, that it is the least constant tissue 
of the teeth; secondly, that its chemical composition 
is very much the same as that of the dentine and 
cement, both of which resemble bone. Lastly, the 
analogy is completed iu a review of the mode of tooth 
development. Thus, upon a mucous papilla a large 
quantity of gelatinous matter is observable, in which 
certain cells appear. The gelatinous matter resembles 
the incipient cartilage in which ossification begins. 
This papilla is supplied with an artery, which nour- 
ishes its cells, and the cells gradually so develop that 
the older ones are pushed outward and form the 
dentine." 

HOW MADDER AFFECTS THE TEETH. 

John Hunter, one of the most celebrated physiolo- 
gists of the eighteenth century, made many experi- 
ments on the teeth of different animals, one object 
being to determine whether they were vascular or not. 
His conclusion was that they were not vascular, and 
he founded his belief partly upon the following experi- 
ment (" The Human Teeth," pp. 23-4) : 

" Take, for example, any young animal, as a pig, and 
feed it with madder for three or four weeks; then kill 
it. On examination you will find the following ap- 
pearances : First, if the animal had some parts of its 
teeth formed before the feeding with madder, they 
will be known by their remaining of the natural color; 
but such parts of the teeth as were formed while the 
animal was taking the madder will be of a red color. 
This shows that it is only those parts that were formed 
while the animal was taking the madder that are dyed ; 



RED, WHITE, GOLDEX, AND SILVER HUES. XXV 

for what were already formed will not be in the least 
tinged. Tiiis is diliereut in all other bones; for we 
know that any part of a bone which is already formed 
is capable of being dyed with madder, though not so 
fast as the part that is forming. Therefore, as we know 
that all otiier bones are vascular, and are thence sus- 
ceptible of the dye, we may readily suppose that the 
teeth are not susceptible of it after being once formed. 
But we shall carry this a step further: If you feed a 
pig with madder for some time, and then leave it off 
for a time before kilhng it, you will lind the appear- 
ances as above, with this addition, that all the parts of 
the teeth which were formsd after leaving off feeding 
with the madder will be white. Here, then, in some 
teeth we shall have white, then red, and then white 
again ; and so we shall have the red and white colors 
alternately through- the whole tooth.* 

"This experiment shows that a tooth, once tinged, 
does not lose its color. Now, as all other bones that 

*In the concluding part of Moore's " Lalla Rookli" ("The 
Light of the Harem"), the Enchantress says of an herb with the 
unmusical name of " Haschischat ed dab:" 

* ' The visions, that oft to worldly eyes 
The glitter of mines unfold,* 
Inhabit the mountain-herb, that dyes 
The tooth of the fawn like gold." 

A reference note to the above is as follows : " An herb on 
Mount Libanus, which is said to communicate a yellow golden 
hue to the teeth of the goats and other animals that graze upon 
it. Nisbuhr thinks this may be the herb which the Eastern 
alchemists look to as a means of making gold. 'Most of those 
alcliemical enthusiasts think themselves sure of success if they 
could but find out tlie herb which gilds the teeth and gives a yel- 
low color to the flesh of the she-^p that eat it. Even the r)il of tins 
plant must be of a' golden color. It is called Haschischat ed dab.' 
Father Jerome Dandini, however, asserts that the teeth of the 



XXVI INTRODUCTION. 

have been tinged lose their color in time, when the 
animal leaves off feeding with the madder (though 
very slowly), and as that dye must be taken into the 
constitution by the absorbents, it seems that the teeth 
are without absorbents as well as other vessels." 

The editor of Hunter's "Treatise," Thomas Bell, 
F.K.S., differed with Hunter about the vascularity of 
the teeth. He thus concludes a note on the above 
quotation : 

"The truth appears to be that the teeth are organ- 
ized bodies, having nerves and absorbent and circula- 
ting vessels, but possessing a low degree of living 
power, and so dense a structure as to exhibit phenom- 
ena, both in their healthy and diseased condition, 
which are very dissimilar from those which are ob- 
served in true osseous structures." 

TRANSPLANTING TEETH. 

The transplanting of teeth, which Dr. Hunter says 
is " similar to the ingrafting of trees," is expatiated 
upon at some length. He then gives an account of a 
case of transplanting which he admits "is not gener- 
ally attended with success," he having "succeeded but 
once out of a great number of trials." It is as follows 
(" The Human Teeth," pp. 100-101) : 

" I took a sound tooth from a person's head ; then 

goats at Mount Libanus are of a silver color, and adds : ' This 
confirms to me that which I observed in Candia, to wit, that 
the animals that live on Mount Ida eat a certain herb which 
renders their teeth of a golden color, which, according to my 
judgment cannot otherwise yjroceed than from the mines which 
are under ground.' — Dandini, Voyage to Mount Libanus" 



Gr^AFTIXG GEP.MS OF DOGS' TEETTT. XXVli 

made a wound in a cock's comb, pressed the root into 
it, and fastened it with threads. The cock was killed 
some months after, and I injected the head with a very 
minute injection. I then put the comb into a weak 
acid. The tooth was softened, and I divided it longi- 
tudinally. Its vessels were well injected, the external 
surface adhering to tlie comb by vessels similar to the 
union of a tooth with the gum and sockets."* 

* MM. E. Magitot, C. Legros, and C. Robin have experimented 
in traD.S[.lanting the follicles or g:'rins of dogs' tee\:h. an account 
of which appears in " Comptes Reudus" for 1874. They say : 

"Our experiments comprised 88 grafts, mostly from newly-born 
dogs, but some were 23 and even 58 days old. The animals 
were invariably sacrificsd by the pricking of the bulbs, and 
the jaws were opened at once, to lay the follicles bare. One-half 
of both jaws thus served to supply the grafts, while the other 
was kept for a standard of comparison. The dogs on which the 
grafts were applied were usually adults, but sometimes of the 
same age and bearing? as those that supplied them. The germs 
were rapidly isolated from the dental gutters, and introduced at 
once. In some instances they were dipped for a few minutes in 
the blood's serum of the sacrificed animal, which was kept by 
the bath (bain-marie) at a temperature of from 30' to ^5° C. 
They were introduced under the skin of the nai>3 of the neck, 
the top of the head, and the dorsal and lumbar reorions. In 36 
cases the process of application consisted of a sim[)le incision and 
the introduction of the graft, 2 or 3 centimeters from the open- 
ing, which was closed by two sutural stitches. In the other 53 
cases a special trocar of an interior diam-ter of 7 millimeters was 
used, which allowed a swifter and surer transplantation, but it 
did not appear to exert an appreciable influence on the results. 

" Ten grafts were made from newly-born dogs on adult guinea- 
pigs, divided as follows : Whole follicles, ; isolated enamel- 
organs, 3 ; bulb alone, 1. The results were all negative— caused 
by resorption and suppuration— corroborating M. Bert's experi- 
ences in grafts between animals of different zoological orders. 

"The 78 other grafts were made on newly-born, young, and 
adult dogs, and were maintained from 13 to 54 days. The 25 
grafts that remained 54 days resorbed themselves. The expcti- 
nients in detail were as follows: 1. Isolated whole follicles, 20. 
2. Fuliicles with a portion of the maxillary bone, 5. 3. Isolated 



XXVlll lis'TRODUCTION. 

This appears to prove that Dr. Hiint?r was right 
when he said that teeth " are capable of uniting with 

bulbs, IG, 4. Bulbs with a cap of rudimentary dentine, 7. 5. 
Isolated caps of dentine, 4. 6. Isolated enamel-organs, with a 
shred of buccal mucous membrane, 19. 7. Enamel-organs, with 
a cap of dentine adhering, 1. The results were : Of the first, 7 
kept alive and grew steadily, except in one instance, in which a 
disturbed nutrition brought on the formation of ^lobulary den- 
tine and irregular stacks of enamel prisms. The second gave 3 
suppurations and 2 resorptions, again corroborating Mons. Bert's 
experiments. The third gave 3 positive results, in two of wliich 
a new cap of dentine was produced, quite regular, but globulous 
and somewhat altered in its nutrition. The other was without 
enamel. In the fourth experiment tlie bulbs could not be found ; 
they underwent resorption. When com]iared with the preced- 
ing experiment, this result is astonishing ; but it should be un- 
derstood that these grafts were maintained from 43 to 5t dnys. 
Of the fifth a single one kept alive, but without sliowing any 
growth. It remained stationary 43 days. The sixth invariably 
ended in resorption, notwithstanding we were careful to graft 
the shred of mucous membrane, which sup})lies tlie organ with 
nutritive vessels. This result is not surprising when the exces- 
sive frailty of this tissue and its lack of vascularity are consid- 
ered. Some of the negative grafts were either reduced in size, 
being evidently in process of resorption, or underwent the oily 
transformation. Others caused abscesses, and were eliminated. 
"Conc'iisions. — 1. The grafts gave favorable results only be- 
tween animals of the same zoological order. 2. The isolated 
whole follicles and bulbs may live and develop themsolves, 3. 
The transplanting of more or less voluminous portions of jaws 
with the follicles failed through suppuration or resorption. 4. 
The grafts of the enamel organ, isolated, seem invariably given 
up to resorption. 5. Under certain circumstances the growth is 
regular, with no other diflference from that in the normal state 
than a noticeable slowness in the phenomena of evolution. 6. 
Under other circumstances there is trouble in the formation of 
the dentine and enamel, the study of which, however, may be ap- 
plied to the elucidation of the phenomena, still so dark, of tooth 
development. 7. The experiments are an acquisition to the lit- 
erature of and may be compare.l with other surgical grafts."* 

* For the translation of the above interesting: article (from the Reports of 
the French Academy) I am indebted to Monsieur C. Raoux. of New York. 



THE TEETH LIVING ORGANISMS. XXIX 

any part of a living body." Mr. Bell thus concludes 
a note on the above case of transplanting: 

" The experiment has an interest attached to it far 
more im]iortant than its having given rise to the tem- 
porary adoption of an objectionable operation. In the 
result of this experiment may be found an interesting 
collateral argument in favor of the organized structure 
of the teeth, and their actual living connection with 
the body. The vessels of the tooth, we are told, were 
well injected, and the external surface adhered everv- 
where to the comb by vessels. To what purpose are 
these vessels formed, what object can be possibly ful- 
filled by the existence of a vascular pulp in the internal 
cavity, and a vascular periosteum covering the external 
surface — so obviously vascular that it was -well injected 
from the vessels of a cock's comb, into which it had 
been transplanted — unless they are intended to flourish 
the bony substance of which the tooth consists, and to 
form the medium of its connection with the general 
system?" 

Prof. Richard Owen says (" Odontography," vol. i, 
p. 470) : 

" The saving of material is the least of the benefits 
gained by this tubular structure of the dentine. The 
vitality of the tissue, which Hunter recognized so 
forcibly, but which, being equally convinced of the 
non-vascularity of the tissue, he was unable to explain 
— ' willing rather to enunciate an apparent paradox ot 
be taunted with dilemma, than yield one iota of either 
of his convictions'* — is explicable by the possible and 

*Prof. Owen quotes from Bell's " notes" in Hunter's "Human 
Teeth." 



XXX INTRODUCTION. 

highly probable fact of a circulation of the colorless 
plasma of the blood through the dentinal tubes. That 
some elementary prolongations of nerve may also be 
continued into these tubes, who can confidently deny ?" 

As Prcf. Owen says the " teeth are always most 
intimately related to the food and habits of the ani- 
mal," it would be interesting and perhaps useful to 
ascertain what effect sugar and other unnsual articles 
of diet would have on horses' teeth. In the interest 
of science, experiments appear to be in order. In this 
connection the following paragraph, a part of which 
may be found in Prof WiUiam Youatt's work, " The 
Horse" (p. 135), the remainder in " The Veterinarian/' 
is interesting : 

" Surgeon Black, of the Fourteenth Dragoons, says 
that sugar was tried as an article of food during the 
Peninsular War. Ten horses were selected, each of 
which got eight pounds a day. They took it very 
readily, and their coats became fine, smooth, and 
glossy. They got no corn, and only seven pounds of 
hay instead of twelve, the ordinary allowance. The 
sugar supplied the place of corn so well, that it would 
probably have been given abroad ; but peace came, and 
with it corn. The horses returned to their usual diet, 
but several of them became crib-biters. The exj^eri- 
ment was made at the Brighton depot, during a period 
of three months. To prevent the sugar from being 
used for other purposes, it was scented with assafetida, 
but the latter did not produce any apparent effect on 
the horses." 



HORSPJS' TEETH. 



CHAPTER I. 

TOOTH-GERMS (ODONTOGENY). 

Periods at wliicli the Germs are visible in the Fetus. — Dentine 
and Enamel Germs. — A Cement Germ in the Foal.— The 
Horse's Upi)cr Grinders said to be developed from Five 
Germs, tha Lower from Four. — Similar development of the 
Human Teeth. — Monsieur Magitot's Researches. 

Furrows in what is subsequently transformed into 
jawbones, in wliieh tooth-germs are, as it were, planted, 
are Nature's first visible preparation for the develop- 
ment of the teeth. According to Prof. William You- 
att, the germs of the temporary teeth are visible seven 
or eight months before the foal is born. Three months 
before its birth the germs of the permanent teeth are 
also visible, a distinct partition separating tliem from 
the temporary. At this tiine, according to Veterinary 
Dentist C. D. House, the capsules or bags (also called 
follicles, sacs, &c.), containing the tooth-pulps* of the 

* The pulp in the cavity of a fuU-groini tooth is a delicate 
mass of connective tiFSu:^ containing both blood-vessels and 
nerves. Its external layer consists of large nucleated cells, the 
odontoblasts, provided with long branching processes which line 
the dental canals. Boll thinks the nerves' delicate terminal 
fibrils accompany the processes into the canals. — Woodward. 

For development of elephant tooth-germs see Appendix. 



3^ TOOTH-GERMS. 

future temporary teeth are about tlie size of small peas. 
They will bear some pressure between the fingers, the 
indentions springing back like those of an India rub- 
ber ball. 

Tiie nature of tooth-germs and the development of 
teeth have been studied with some diligence by scien- 
tific men — Dr. John Hunter, it is said, making the first 
important discoveries in connection with the science. 
The discussion of this interesting and, to students, 
useful subject is left to these men. There is some 
conflict in their views, but it should be remembered 
that the extracts reflect tiie opinions of men from 
Hunter's time (over a century ago), to 1876. The de- 
velopment* of tooth-germs being the same in principle 
(though different in detail) in all mammals, the matter 
which follows (as has been said of that in the "Intro- 
duction"), is as applicable to the horse as to man. 

In the Introduction to his "Odontography" (Lon- 
don, 184-4), Prof. Eichard Owen says: 

"In the development of a tooth a matrix of equal 
complexity was first recognized to be concerned by 
John Hunter, the several parts of this matrix being 
first distinctly indicated in the * Natural History of 
the Human Teeth.' * * * Hunter has been gen- 
erally regarded by physiologists as being the author of 
the theory that the pulp stood to the tooth-bone in the 
relation of a gland to its secretion ; that the formative 
virtue of the pulp resided in its surface ; that the den- 
tine was deposited upon and by the formative or secre- 
tive surface in successive layers, and that the pulp, 
exhausted, as it were, by its secretive activity, dimin- 
ished in size as the formation of the tooth proceeded, 
except in certain species, in which it was persistent, 



JciiN huxteb's discovery. 33 

and maintained an equable secretion of the dentine 
throughout the lifetime of the auimal. This idea of 
the pulp's function has predominated in the minds of 
most subsequent writers on the development of the 
tectii. * * * * 

" Three formative organs are developed for the three 
principal or normal dental tissues, the 'dentinal-pulp/ 
or puip proper, for the dentine, the 'capsule' for the 
cement, and the 'enamel-pulp' for the enamel. The 
essential fundaniental s'tructure of each formative 
organ is cellular, but the cells differ m each organ, 
and derive their specific characters from the properties 
and metamorplioses of their nucleus, upon which the 
specific microscopical characters of the resulting calci- 
fied substances depend. 

" In the cells of the dentinal-pulp the nucleus fills 
the parent cell with a progeny of nucleoli before the 
work of calcification begins. In the enamel-pulp the 
nucleus of the cell disappears, like the cytoblast of the 
embryo plant m the formation of most vegetable tis- 
sues. In the cells of the capsule the nucleus neither 
perishes nor propagates, but retains its individuality, 
and gives origin to the most characteristic feature of 
the cement, viz., the radiated cells. 

"The primordial material of each constituent of the 
tooth -matrix is derived from the blood, and special 
arrangements of tlie blood-vessels preexist to the devel- 
opment and growth of the constituent substances. A 
pencil of capillaries is directed to a particular spot in 
the primitive dentiparous groove, and terminates there 
by a looped network, from which spot a group of nu- 
cleated cells begins to arise in the form of a papilla. 
* . * * * * 

"The primary dentinal papilla and its capsule rap- 



34 TOOTH-GERMS. 

idly increase by successive additions of nucleated cells^ 
apparently derived from material supplied by the cap- 
illary plexus at the base. The capillaries now begin 
to penetrate the substance of the pulp itself, where 
they present a subparaliel or slightly diverging pencil- 
late arrangement, but preserve their looped and retic- 
ulate termination near the apex of the pulp. Fine 
branches of nerves accompany the capillaries, and ter- 
minate also in loops. * * * The primary cells and 
the capillary vessels and nerv^es are imbedded in and 
supported by a homogeneous, minutely subgranular, 
mucilaginous substance, the 'blastema.' * * * The 
vascularity of the dentinal-pulp, and especially the 
rich network of looped capillaries that adorns the 
formative peripheral la3^er at the period of its func- 
tional activity, have attracted general notice, and have 
been described by Hunter and subsequent authors. By 
most this phenomenon has been regarded as evidence 
of the secreting function of the surface of the pulp, 
and the dentine as an outpouring from that vascular 
surface which was supposed to shrink or withdraw 
from the matter excreted. * * * 

" The enamel-pulp differs from the dentinal-pulp at 
its first formation by the more fluid state of its blas- 
tema, and by the fewer and more minute cells which 
it contains. The source of this fluid blastema appears 
to be the free inner vascular surface of the capsule. 
As it approaches the dentinal-pulp the blastema ac- 
quires more consistence by an increased number of its 
granules, and it contains more numerous and larger 
cells. Many of these show a nuclear spot, others a 
nucleus and nucleolus. The spherical nucleolar cells 
in the part of the blastema further from the capsule 
are so numerous as to form an aggregate mass, with a 



DEFIXIXG THE Bh.VSTEMA. 36 

small quantity of the condensed blastema in the 
minute interspaces left between the cjIIs, which are 
pressed together into hexagonal or polygonal forms. 
* * * The field of the final metamorphosis of the 
cells into the molds for the reception of the solidifying 
salts is confined to close contiguity with the surface of 
the dentinal pulp. Here the cells increase in length, 
lose all trace of their nucleus, and become converted 
into long and slender cylinders, usually pointed at both 
ends, and pressed by mutual contact into a prismatic 
form. These cylinders have the property of imbibing 
the calcareous salts of the enamel from the plasmatic 
fluid, and of compacting them in a clear and almost 
crystalline state in their interior. * * * 

"The blastema or fundamental tissue of the capsule 
is, at first, semitransparent and of a pearly or opahne 
color, but IS soon richly ornamented by the plexiform 
distribution of the blood-vessels. As the period of its 
calcification approaches, which is later than that of 
the dentinal-pulp, it becomes denser, and exhibits nu- 
merous nucleated cells. The blastema itself presents 
more evidently a fine cellular or granular structure, in 
Avhich the calcareous salts are impacted in a compara- 
tively clear state, constituting the framework of the 
cemental tissue. The characteristic features of this 
tissue are due to the action of the proper nucleated 
cells upon the salts of the plasma diffused through the 
blastema in which those cells are imbedded, the cells 
being characterized by a single, large, granular nu- 
cleus, which almost fills the clear area of the cell itself 
If, when the formation of the cement has begun m the 
incisor or molar of a colt, one of the detached specks 
of that substance, with the surrounding and adhering 
part of the inner surface of the capsule in which it is 



36 TOOTH-GERMS. 

imbedded, be examined, the nucleated cells are seen, 
closely aggregated around the calciiisd part, in con- 
centric rows, the cells of which are further apart as 
the rows recede from the field of calcification. Those 
next the cement rest in cup-shaped cavities in the 
periphery of the calcified part, just as the first calcified 
cells of the thick cement which covers the crown of a 
complex molar are lodged in cavities on the exterior of 
the enamel. These exterior cavities of the cement are 
formed by centrifugal extension of the calcifying pro- 
cess m the blastema m which the cells are nnbedded. 
The calcareous salts penetrate m a clearer and more 
compact state the cavity of the cell, but their progress 
is arrested apparently by the nucleus, which maintains 
an irregular area, partly occupied by the salts in a sub- 
granular, opake condition, but chiefly concerned in 
the reception and transit of the plasmatic fluid, which 
enters and escapes by the minute tubes that are sub- 
sequently developed from the nucleolar cavity as calci- 
fication proceeds. 

'- The radiated cells or cavities thus formed are the 
most common characteristic of the cement, but not the 
constant one. The layer of the capsule which sur- 
rounds the crown of the human teeth and of the 
simple teeth of quadrumana and carnivora, consists 
simply of the granular blastema, without nucleated 
cells, and the radiated corpuscles are, consequently, not 
developed m the cement v,'hich results from its calci- 
fication. In the thicker part of the inflected folds of 
the capsule of the complex teeth of the herbivora, 
traces of the vascularity of that part of the matrix* are 
persistent, the blastema calcifying around certain of 
the capillaries, and forming the medullary canals. 
The varieties of these canals are traversed by minute 



PROF. TOMES'S THEORY. 37 

tubules, continuetl from or communicating with the 
radiated cells. These tubules, and the more parallel 
ones which traverse the thickness of the cement in 
many mammalia, are the remams of linear series of 
the minute granules of the blastema. * * * 

*' The general form of the dental matrix and its rela- 
tion with its calcified product, bear a close analogy 
with those of the formative organ of hairs, bristles, and 
other productions of the epidermal system. In these 
the papilla, or pulp, is developed from the external 
skin; in the teeth, from the mucous membrane, or 
internal skin." * * * * 

Prof. Charles S. Tomes, among dentists a recognized 
authority, differs with Messrs. Hunter and Owen as 
to the pulp's secretive office, claiming that a tooth is 
formed by a partial metamorphosis of its pulp. He 
says ('* Manual of Dental Anatomy, Human and Com- 
parative," pp. 104-5-6) : 

" Prior to the beginning of any calcification, there 
is always a special disposition of the soft tissues at the 
spot where a tooth is destined to be formed, and the 
name of ^ tooth -germ' is given to those portions of the 
soft tissue which are thus specially arranged. All, or 
a part only, of the soft structures making up a tooth- 
germ become converted into the dental tissue by a 
deposition of salts of lime within their own substance, 
80 that an actual conversion of at least some portions 
of the germ into tooth takes place. The tooth is not 
secreted or excreted by the germ, but an actual meta- 
morphosis of the latter takes place. 

" The principal tissues, namely, dentine, enamel, and 
cement, are formed from dilierent parts of the tooth- 
germ; hence we are accustomed to speak of the enamel- 



38 TOOTH-GERMS. 

germ and tlie dentine-germ. The existence of a spe- 
cial cement-germ is very doubtful, some writers assert- 
ing, others denying its existence. * * * 

" Tooth-germs are never formed upon the surface, 
but are situated a little distance beneath it, lying in 
some animals at a considerable depth. Every known 
tooth-germ consists in the first instance of two por- 
tions, and two only, the enamel and dentine germs. 
These are derived from distinct sources, the former 
being a special development from the epithelium of 
the mouth, the latter from the more deeply lying parts 
of the mucous membrane. Other things, such as a 
tooth-capsule, may be subsequently and secondarily 
formed. The existence of an enamel-organ in an early 
stage is independent of any subsequent formation of 
enamel by its own conversion into a calcified tissue, for 
I have shown it to be found in the germs of teeth 
whicli have no enamel; in fact, in all tooth-germs 
whatever. 

"That part of the tooth-germ destined to become 
dentine is often called the dentine papilla, having 
acquired this name from its papilliform shape; and in 
a certain sense it is true that the enamel-organ is the 
epithelium of the dentine papilla. Yet, although not 
absolutely untrue, such an expression might mislead 
by implying that the enamel organ is a secondary de- 
velopment, whereas its appearance is contemporaneous 
"with, if not antecedent to, that of the dentine-germ. 
The most general account that I am able to give of the 
process is, that the deeper layer of the oral epithelium 
sends down into the subjacent tissue a process, the 
shape and structure of which is, in most animals, dis- 
tinguishable and characteristic before the dentine- 
germ has taken any definite form. This process en- 



THE ORAL EPITHELIUM. 39 

larges at its end, and, as seen in section, becomes 
divaricated, so that it bears some resemblance to an 
inverted letter Y ; or it miglit be better compared to a 
bell-jar with a handle. This constitutes the early stage 
of an enamel-germ, while beneath it, in the mucous 
tissue, the dentine-germ assumes its papilliforni shape. 
The details of the process varying in ditferent animals, 
I will at once proceed to the description of the devel- 
opment of teeth in the various groups." 

Prof. Tomes^s views of the development of tooth- 
germs in mammals are thus summarized by himself 
("Philoso])hical Transactions Royal Society,'' 1875, 
part i, p. 285) : 

'^1. There is never, at any stage, an open groove 
from the bottom of which papilla3 rise up. 

"2. That the first recognizable change in the region 
of a forming tooth-germ is a dipping down of a process 
of the oral epithelium, looking, m section transverse 
to the jaw, like a deep simple tubular gland, which 
descends into the submucous tissue, and ultimately 
forms the enamel-organ. 

" 3. That subsequently to the descent of the so-called 
enamel-germ, the changes in the subjacent tissue re- 
sulting in the formation of the dentine papilla take 
place opposite to its end, and not at its surface. 

"4. That the permanent tooth-germs first appear as 
offshoots from the epithelial process concerned in the 
formation of the deciduous tooth-germ (Kolliker), the 
first permanent molar being derived from a primary 
dipping down (like a deciduous tooth), the second de- 
riving its enamel-germ from the epithelial neek of tlic 
first, and the, third from that of the second (Legros 
and Magi tot)." 



40 TOOTII-GEllMS. 

Again, in the Society's Transactions for 1876 (p. 265), 
Prof. Tomes says : 

"1. It is desirable to abandon the terms 'papillary/ 
'follicular/ and 'eruptive' stages, inasmuch as they 
are hypothetical and arbitrary, and correspond to no 
serial conditions veriiied by observation. 

"2. In all animals a tooth-germ consists primarily 
of two structures, and only two — the dentine-germ 
and the enamel-germ. The simplest tooth-germ never 
comprises anything more. When a capsule is devel- 
oped, it is derived partly from a secondary upgrowth 
of the tissue at the base of the dentine germ, and partly 
from an accidental condensation of the surrounding 
connective tissue. 

'•'3. The existence of an enamel-organ is quite uni- 
versal, and is in no way dependent on the presence or 
absence of enamel on the completed tooth, although 
the degree to which it is developed has distinct relation 
to the thickness of the future enamel. 

"4. So far as my researches go, a stellate reticulum, 
constituting a large bulk of the enamel-organ, is a 
structure confined to the mammalia. (It is absent in 
the armadillo, and I should infer from Mr. Turner's 
description, in the narwhal also). 

"5. x\s laid down by Profs. Huxley and Kqlliker, 
the dentine-papilla is beyond all question a dermal 
structure, the enamel-organ an epithelial or epidermic 
structure. As I believe it can be shown that the enamel 
is formed by an actual conversion of the cells of the 
enamel-organ, this makes the dentine a dermal and 
the enamel an epidermic structure. 

"6. In teleosts the nev/ enamel-germs are formed 
directly from the oral epithelium. They are new for- 
mations, and arise quite independently of any portion 



MONSIEUR CHAUVEAU'S THEORY. 41 

of the germs of the teeth which preceded them. In 
mamraals and reptiles, and in some of the batrjicliia, 
new tooth-germs are developed from })ortions of their 
predecessors. 

"7. in all animals ex?imined the phenomena are very 
uniform. A process dips in from the oral epithelium, 
often to a great depth, its end becoming transformc^d 
into an enamel-organ coincidentally with the formation 
of a dentine-papilla beneath it. The differences lie 
rather in snch minor details as the extent to which a 
capsule is developed, and therefore no such generali- 
zation as that the teeth of fish in their development 
represent only an earlier stag-3 of the development of 
the teeth of mammalia can be drawn." 

Monsieur A. Chanveau's theory of the development 
of tooth-germs is as follows (" Comparative Anatomy 
of the Domesticated Animals,'^ p. 921) : 

" The teeth are developed in the interior of a cavity, 
named the dental follida or sac, by means of the ele- 
ments of three germs, one belonging to the dentine, 
another to the enamel, and a third to the cement. The 
dental follicle is an oval cavity, with walls composed of 
two layers. The external is fibrous and complete ; the 
internal, soft and gelatinous, is allied at the bottom to 
the dentine-germ. The latter is a prominence, which 
is detached from the bottom of the follicle, and has 
the exact shape of the tooth. Its structure comprises, 
in the center, delicate connective tissue, provided with 
vessels and nerves, and on the surface a layer of elon- 
gated cell.N At the summit of the follicle, facing the 
dentine-germ, is the enamel-germ. It is exactly ap- 
plied to the dentiual-pulp, which it invests like a cap. 



42 TOOTH-GERMS. 

and is composed of a small mass of mucous connec- 
tive i^ssue, covered by a layer of cylindrical cells, and 
joined to the buccal epithelium by the guhernaculum 
clentis.^ Accordiug to Monsieur Magitot, the cement- 
organ manifestly exists in the foal. The base of the 
de II tine-germ has been found, but it disappears rapidly 
after having performed its function. 

'^Development of the Dental Follicle. — On the free 
borders of the maxillae, the epithelium of the buccal 
mucous membrane forms an elongated eminence — the 
dental ridge. Below this ridge the epithelium consti- 
tutes a bud, which develops in size, and is sunk in the 
mucous membrane. This is the enamel-germ. It has 
a layer of cylindrical cells on its deep surface, and in 
its center are round cells. After a certain time it is 
only joined to the epithelium, as already said, by a very 
thin line of cells, the gu'bernaculiim dent is. While this 
enamel-germ grows downward, it covers, by its base, a 
connective bud w^hich rises from the mucous derma. 
The two buds are reciprocally adapted to each other, 

* Coueerning the gubernaculum dentis Prof. C. S. Tomes says 
(" Dental Anatomy," p. 135): "Another structure, once thought 
to be important, but now known to be a mere bundle of dense 
fibrous tissue, is the ' gubernaculum.' The permanent tooth 
sacs, durinor their growth, have become invested by a bony shell, 
which is complete, save at a point near their apices, where there 
is a fora'men. Through this foramen passes a thin fibrous cord, 
very conspicuous when the surrounding bone is broken away, 
which is called the gubernaculum, from the notion entertained 
by the older anatomists that it was concerned in directing or 
eflTecting the eruption of the tooth. The gubernacula of the 
front permanent tooth sacs perforate the alveolus and blend with, 
the gum behind the necks of the corresponding milk teeth, 
those of the bicuspids uniting with the periosteum of the alveoli 
of their deciduous predecessors." 



THE DENTINE-GERM TOOTH-SHAPED. 43 

and around them the connective tissue condenses and 
gives rise to the walls of the follicle, it will therefore 
be seen that the enamel-organ is a dependency of the 
epithelium, and the dentine-organ a production of the 
mucous derma. 

'■^Formation of the Dentine, Encunet, and Cement. — 
As before said, the gei'm of the dentine has exactly the 
form of the future tooth; consequently the dentine 
which arises from its periphery presents the shape of 
a tooth also. The dentine and enamel are developed 
by the modification of the elements situated at the 
surface of their germs. The dentine is constituted of 
the cells of the germ, which send out ramifying and 
communicating prolongations — the dentinal fibers — 
and by an intarcellular substance, which is impreg- 
nated with calcareous matter, and which, being molded 
around the fibers, forms canal iculi. The enamel is 
derived from the deep cells of its germ, which are 
elongated and prism-shaped, and are calcified in be- 
coming applied to the surfi.ice of the dentine. The 
cement is developed at the expense of the walls of the 
follicle, according to the mode of ossification of the 
connective tissue. 

''Eruption. — As the dentine is formed, the tooth 
increases in length and presses the enamel-germ up- 
ward. The latter, constantly compressed, becomes 
atrophied, and finally disappears when the tooth has 
reached the summit of the follicle. In the same way 
the young organ pierces the dental follicle and gum 
and makes its eruption externally. 

"Such is the mode of the development of the tem- 
porary teeth, and the permanent ones are formed in the 
same inanner. During the development of the germ 
of the temporary tooth, a bud is seen detaching itself 



44 TOOTH-GEEMS. 

from this germ and passing backward, to serve, at a 
later period, in forming tlie permanent tooth/' 

111 another part of his work Prof Chauveau says: 

"The follicle in which the incisor teeth are devel- 
oped shows only two papillae. One, for tlie secretion 
of the dentine, is lodged in the internal cavity of the 
tooth, and is hollowed into a cup-shape at its free ex- 
tremity; the other is contained in the external cul-de- 
sac." 

In describing the simplicity of the structure of the 
horse's canine teeth (tushes), Prof. Lecoq says: 

^'The disposition of tlie developing follicle is in har- 
mony with the simplicity of their structure. At the 
bottom there is a simple and conical papilla for the 
internal cavity; on the inner wall, a double longitu- 
dinal ridge, on which are molded the ridge and grooves 
on the inner f ice of the tooth." 

Prof William Youatt's theory of the development 
of horses' teeth is unique. He is probably correct 
about the bones or processes being separate, and his 
claim that they are solidified by the cement is certainly 
philosophical ; but he differs from all other authorities 
about the enamel completing the formation of the 
tooth, for it is a Avell- known fact that a virgin tooth 
is enveloped by cement (its protecting varnish), which 
wears off as soon as the tooth is brought into use. He 
says ("The Horse," p. 223) : 

"A delicate membranous bag, containing a jelly-like 
substance, is found in a little cell within the jawbone 
of the unborn animal. It assumes by degrees the 
shape of the tooth, and then the jelly begins to change 



GREAT USE OF TUE CEMEXT. 



45 




:he baos, and there 



to boil}' matter. A liard and beautiful crystallization 
is formed on the membrane without, and so we have 
the cutting tooth covered by its enamel. 

" 111 the i'orination of the grinders there are origin- 
ally five membranous bags in the upper jaw and four 
in the lower. The jelly in them 
gives place to bony matter, 
which is supplied by little ves- 
sels, and which is represented 
by the darker portions of the 
cut with central black spots. 
The crystalhzation of enamel 
may be traced around each of 
would be five distinct bones or teeth but for the fact 
that a third substance is now secreted. (It is repre- 
sented by the white spaces). It is a powerful cement, 
and through its agency the bones are united into one 
body, thus making one tooth of the five. This being 
done, another coat of enamel spreads over the sides, 
but not the top, and the tooth is completed." 

Dr. Robley Dunglison's theory of the development 
of the human teeth is in principle the same as Prof. 
Youatt's theory regarding those of the horse. In his 
"Medical Dictionary," article "teeth," he saj-s: 

"The incisor and canine teeth are developed by a 
single point of ossification, the lesser molars by two, 
and the larger by four or five." 

Surgeons M. H. Bouley and P. B. Ferguson believe 
that the teeth are the combined product of the secre- 
tion of the [)ulp and of the membrane which lines tlie 
alveolar cavities. They say that the quesiion as to 
whether the sensibility of the teetii is inherent in the 
dental substance itself, or resides exclusively in the 



46 TOOIH-GEllMS. 

pulp, is a physiological point of which a satisfactory 
solution remains to be given.* 

* Of tlie development of teetli in the human fetus Monsieur 
E. Magitot says (" Comtes Rendus," 1874): "Seocnth Week — 
The epithelial eminence and epithelial inti^ction of Kolliker 
only may be seen at the edge of the jaw. The superior maxil- 
lary aud intermaxillary bones are not uuiteJ, and the inferior 
maxillary arch contains Meckel's cartilage only, without any 
trace of bone. The epithelial bands (enamel-organs) are succes- 
sively formed in the order of their designation. Ninth — The 
dentine bulb appears in juxtaposition with the downward ex- 
tremity of the enamel-organ. This stage occurs nearly simul- 
taneously for the whole series of temi o..i.y follicles. Tenth — 
The wall of the follicle detaches itself from the base of the bulb 
and rises uj) its sides. Fifteenth — The epithelial band begins 
its transformation into an enamel-organ. The enamel-germ of 
the first permanent molar may now be seen springing from the 
epithelial inflection. Sixteenth — The wall of the follicle is 
closed. The epithelial band is broken, and the follicle thencefor- 
ward has no connection with the surface epithelium. The epi- 
thelial bands of the permanent teeth, which are derived from the 
necks of the enamel-organ of the corresponding deciduous teeth, 
appear. S-.'venteenth — Appearance of the cap of dentine of the 
central and lateral incisors ; also the bulb of the first permanent 
molar. Eijjhtecnth — Appearance of the dentine caps of the first 
and second molars ; also the wall of the follicle of the perma- 
nent mo'ar. Ticentieth—R\g\\t of the dentine caps of the cen- 
tral incisor, lateral incisor, and canine, .059 ; first and second 
molars, .039. Appearance of dentine organ of permanent teeth, 
and inclosure of wall and rupture of band of first molar. Twenti/- 
jiftfi — Dentine cans, .07, .054. The permanent follicle walls, 
which ajipeared after the twenty-first week, have acquired a cer- 
tain distinctness. Ticeiity-eifjhth — Dentine caps, .093, .078. The 
epithelial germs of the permanent follicles begin their transfor- 
mation into enamel-organs; dentine cap first molar, .003 to .007. 
Thirty -second — Dentine caps, .113, .093. The first permanent 
molar cusps, which form upon the several apices of the dentine 
organ, have coalesced. Thirty-sixth — Dentine caps, .118, .109; 
permanent molar, .004 to .039. Thirty-ninth— Tfewtme caps, 
.136, .118 ; permanent molar, .039 to .073. The permanent f .^llicle 
walls close. The dentine caps appear one month after birth." 



CHAPTER II. 

THE TEMPORARY DEXTITIOIT. 

Twelve Incisors and Twelve Molars.— Why tlie Incisors are 
called " Nippers."— The Treatment of Foals Affects Teeth- 
ing.— Roots of Milk Teeth Absorbed by the Permanent. 
—The Tushes. 

The foaFs temporary teeth (known also as milk or 
deciduous teeth) are adapted in size and number to 
the capacity of the jaws and the amount and nature 
of the mastication required for its sustenance. There 
are only twenty-four temporary teeth functionally de- 
yeloped. They consist of twelve incisors or nippers* 
and twelve molars or grinders, six above and six below 
of each kind. The dental formula is expressed thus : 

Incisors, f — |; molars, |- — f=^4. 

According to Veterinary Dentist C. D. House, who 
says the care and treatment of foals will affect the 
growth of their teeth as much as they Avili their gen- 

^ Horsemen call the incisor teeth "Nippers." The word ex- 
presses the office they perform, to wit, nippinjr grass, iis well as 
the word "grinder" does in the case of the molars — grinding 
corn. They call the first pair of incisors "central nippers," or 
" centrals," one being on either side of the median line ; the 
second pair are the "di\iders," for they stand between the first 
and third paii^ ; the third pair are called the "corners," from 
their forming the points of the crescent like figure. 



48 THE TEMPORARY UENTITIO^T. 

eral development, the foal lias no teeth at birth, Na- 
ture providing a membrane-like cover for tlie incisors 
as well as the lioofs. In two or three days, however, 
the molars are all cut. The incisors are cut in pairs, 
two above and two below. The first pair protrude in 
from three to eight days, and attain their growth in 
about two months. The second pair are cut when the 
foal is five or six weeks old. Th^y also attain their 
growth in about two months. The time of cutting the 
third pair varies. In some foals they appear as early 
as the sixth month ; in others as late as the ninth. 
They attain their growth in about three months.* 

The milk teeth are smaller and wdiiter and have 
more distinct necks than the permanent. Their shin- 
ing, milky-white color, M. Chauveau says, is due to 
the thinness or absence of the cement, their crowns 
being finely striated (not cannular) on the anterior 
face, and their growth, unlike the permanent teeth, 
ceasing when they begin to be used.f 

'•' M. Rousseau assigns from the seventh to the tenth month 
as the period of the completion of the first or colt's mouth den- 
tition. The deciduous incisors have thinner and more trenchant 
crowns than the permanent. — Owen. 

•f- The absorption of the roots of the milk teeth by the per- 
manent would tend to prevent the continuous growth of the 
former ; but the real cause appears to be that continuous growth 
is contrary to their nature. As the roots are composed of 
cement (except the dentine lining the pulp cavity), and as 
they are absorbed, it naturally follows that much of the cement 
surrounding the crowns of the permanent teeth is derived from 
them (cement from cement), thus lessening the drain on the 
pennanent tooth pulps, which are all the better able to supply 
cement for the roots of the permanent teeth. The scarcity of 
cement on the crowns of tlie milk teeth is probably owing to 
the fact that they had no cement to absorb. The evil of extract- 
in<x healthy milk teeth is obvious. 



SHED OR ABSORBED. 49 

The incisors, which stand in an almost upright 
position, are smooth and rounded on the outer sur- 
face, but grooved on the inner. Their average length, 
including the root, is about an inch, their width 
about half an inch. The molars are about an inch 
and a quarter in length, and nearly an inch in long 
(antero-posterior) diameter. The short (transverse) 
diameter of the upper molars, which is about three- 
fourths of an inch, exceeds that of the lower nearly a 
half. Surgeon John Hughes says that in proportion 
to tlieir length the breadth * of the temporary teeth is 
greater than the permanent. When first cut the in- 
cisor teeth are very sharp ; the outer edges are higher 
than the inner, tlie slant resembling that of a chisel. 
A little wear, however, dulls the teeth, and brings the 
edges to a common level. The contrast between the 
edges of the corner incisors, however, is distinct for 
some time, the outer edge wearing off slowly. 

There is a marked contrast in the appearance of the 
incisors at the age of one year and about the close of 
the second. At the former period they look new and 
fresh, standing close together, while at the latter they 
not only look old and worn, but the development of 
the jaws has caused them to stand apart. Their nar- 
row necks are also conspicuous at two years of age. 

The incisors are shed in the order in which they are 
cut. Nature provides them as they are needed, and 
takes them away so as to cause the least inconvenience 
to the foal. During the shedding of the central inci- 
sors foals have the use of the dividers and corners. 
The permanent centrals are ready for use before the 
dividers are shed, and the permanent dividers are 

*" Breadth is antoro-]wsterior diameter; thickness is trans- 
verse diameter." — B. Owen 
3 



50 THE TEMrORAHY DEKTITIOlf. 

ready before tlie corners are shed. However, during 
the shedding periods, particularly that of the central 
teeth, foals experience more or less difficulty in graz- 
ing; but if they are given a moderate quantity of soft, 
green food, their health will not be impaired, nor will 
they lose much flesh. 

The central incisors are shed when the foal is about 
two years and a half old, the dividers at three and 
a half or four, and the corners at four and a half or 
five. 

The molars, which Prof. Richard Owen says sc^oner 
begin to develop roots than the permanent, are shed 
with even less inconvenience to the foal than the in- 
cisors. The fourth grinder, the first permanent tooth 
cut, is ready for use before the first temporary molar 
is shed, and the fifth and sixth are ready before the 
second and third are shed. The time of shedding tlie 
twelve teeth varies somewhat, and the falling off of 
the "caps" of the uppers will precede those of the 
lower teeth several weeks. The caps are all that is 
left of the temporary molars, their roots and perhaps 
a small part of their bodies having been absorbed by 
the permanent. In most cases fully four-fifths of 
the crowns are worn off by attrition. Thus, when 
Nature is let alone, the temporary teeth are absorbed 
rather than shed; but when a shell is loose and in the 
way, it does no harm to remove it. The first molar is 
shed about the end of the second year, the second 
about the end of the third, and the third about the 
end of the fourth. 

Surgeon W. A. Cherry says that the shedding of the 
teeth usually occurs in the Spring. There is, he says, 
a sufficient interval of time between the shedding of 
the upper and lower molars for the new teeth in the 



UNFUJTCTIONALLY DEVELOPED CANIXES. 51 

upper jaw to meet the old ones in the lower; sometimes 
the respective teetli, when the cajis fall oil", are not more 
than the sixteenth of an inch apart. He also says that 
as the temporary teeth wear dow^n they become less 
and less dense. 

While, as before said, it does no harm to remove 
loose shells, the punching out of a pair of incisors, 
which is sometimes done for the purpose of deception, 
frequently causes serious injury to the permanent 
pair (which should absorb the temporary, and fill the 
space that has become too large for it), not to mention 
the interference with grazing. The temporary teeth are 
often broken off at the neck and the sockets injured; 
this sometimes causes the permanent to grow irregu- 
larly, which ill the case of the horse is a very serious 
matter, for if the permanent teeth do not meet, and are 
consequently not worn off by attrition, their growth, 
which continues throughout life, will cause trouble. 
There are cases, iiowever, such as abnormal growths, 
accidents, &c., in which it is necessary to remove the 
temporary tooth, but the forceps only should be used. 
When the teeth have been removed for the purpose of 
deception, the object is to make it appear that they 
have been shed, and that the animal is older than it 
really is. 

Veterinary authors, as a rule, do not mention the 
temporary tushes. A few odontologists, however, have 
described them. Prof. Owen (" Odontography," vol. i, 
p. 580) says "the small deciduous canine" is cut about 
the sixth month, at the time the third or corner inci- 
sors are cut. The lower tush, owing to its diminutive 
size, and its being so close to the incisor, "is shed 
almost as sooit as the crown of the contiguous incisor 
is in full place, being carried out by the same move- 



52 THE TEMPORARY DEKTITIOi^. 

ment" Bojanns,* Prof. Owen says, first "drew the 
attention of veterinary authors to it by his memoir 
' De Dentibus Caninis Caducis/ &c. Bojanus never 
found the lower deciduous canine retained beyond the 
first year. The deciduous canine of the upper jaw, 
being- developed at a short distance behind the incisors, 
is less disturbed by the eruption of the outer incisor, 
but is nevertheless shed in the course of the second 
year. The deciduous canines appear from Camper's f 
observations to retain their place longer in the zebra 
than in the horse." 

Monsieur Lecoq says: 

" The canine teeth are not shed, and grow but once. 
Some veterinarians, and among them Forthomme and 
liigot, witnessed instances in which they were replaced ; 
but the very rare exceptions cannot make us look upon 
these teeth as liable to be renewed. We must not, 
however, confound with these exceptionable cases the 
shedding of a small spicula or point, which, in the 
majority of horses, precedes the eruption of the real 
tusks.'' 

Prof. C. S. Tomes says: 

" The milk teeth of all the ungulata are very com- 
plete, and are retained late. They resemble the per- 
manent teeth in general character, but the canines of 
the horse, as miglit have been expected — their greater 
development in the male being a sexual character — are 
rudimentary in the milk dentition." 

* " Nova Acta Nat. Curios., torn, xii, part ii, p. 697. 1825." 
f '* CEuvres de Pierre Camper. Paris, 1805." 



CHAPTER III. 

THE PERMAI^ENT DEN^TITION". 

Distinction between Premolars and Molars. — The Bow-like In- 
cisors. — Contrasts between the Upper and Lower Grinders, 
and the Rows formed by them. — The Incisors saved from 
Friction. — Horses' Teeth compared with those of other An- 
imals.— Measurements. — Time's Changes. — Growth daring 
Life. 

The Permanent Teeth, owing to their increased size 
and number, are as well adapted to the needs of the 
horse as the temporary are to the foal. In the males 
forty teeth are functionally developed ;* in the females 
thirty-six, the latter, as a rule, having no canine teeth. 
However, their rudiments exist in the jaws, and some- 
times, especially in old age, protrude. Of the forty 
teeth in the male horse there are twelve incisors, four 
canines or tushes (also called cannon or bridle teeth), 
twelve premolars,! and twelve molars. The dental 
formula is expressed thus : 

I.,|-|; C.,{-{; p. M.,J-|; M., 1-1=40. 

* The teeth that are not functionally developed are treated of 
in the chapter entitled " Remnant Teeth." 

f "Premolars are teeth in front of the molars; they usually 
diflfer from them by beinpc smaller and more simple in form, and 
in most animals iiave displaced deciduous predecessors. But 
they are not always smaller nor simpler in form {r. g., the 



54 THE PERMAJiTEN'T DENTITION". 

The incisors and premolars absorb and replace the 
entire temporary dentition, except the shells or caps 
described in the preceding chapter, but the canines 
and molars are cut through the gums. 

In yeterinary works, as a rule, no distinction is made 
between a premolar and a molar, the twenty-four back 
teeth being called either molars or grinders. Prof. 
C. S. Tomes says the premolars and molars " are very 
similar to one another in shape, size, and in the pat- 
tern of their grinding surface." There is a difference, 
however, between the respective teeth, and naturalists 
make a distinction. The premolars (the three first 
back teeth), which replace the temporary molars, are 
slightly larger than the molars (the three last back 
teeth). They have besides a backward inclination, 
while the molars incline forward ; the respective teeth 
are thus set toward one another. Both kinds are 
properly called grinders. 

The permanent teeth are cut in pairs, two in either 
jaw, the upper teeth preceding the lower from one to 
two weeks. In the cutting of the canines, however, 
the reverse is the rule, for the lower teeth precede the 
upper. About a year's time elapses between the cut- 
ting of the respective pairs of teeth ; that is, when the 
central incisors are cut, it will be about a year before 
the dividers will emerge. The rule is applicable to 
the premolars and molars also, but the case is different, 
for twenty-four of these teeth have to be cut during 

horse) ; nor do they always displace deciduous predecessors 
{e. g., they do not all do so in the marsupials) ; so that this defi- 
nition is not absolutely precise. Still, as a matter of practice, 
it is usually easy to distinguish the premolars, and the division 
into premolars and molars is useful."— 6'. 8, Tomes, "Dented 
Anatomy," dr., p. f?58. 



TIME OF CUTTING. 55 

the same period of time that the twelve incisors are 
cut. A permanent tooth attains its growth in about a 
year. 

According to the best authorities, the molar and 
canine teeth are cut at the following periods: The 
first molars (in veterinary works they are called the 
fourth, because the three premolars come in front of 
them) are the first permanent teeth cut. The time of 
their cutting varies, for tiie foal's jaws must be suffi- 
ciently developed to afford them room, notwithstand- 
ing tliey are usually the smallest of the six back teeth. 
They are cut about the beginning of the second year, 
and are generally ready for use by the time the foal is 
two years old. The second molars are cut at about 
the age of two years, and are therefore fully developed 
by the end of the third year. The third pairs, the last 
of the molars, and conseijuently the most posterior of 
all the teeth, are sometimes cut as early as the third 
year, in which case they would be developed by the end 
of the third or the beginning of the fourth year. The 
time, however, may be prolonged six months or more. 
The canine teeth (tushes) emerge at or near the be- 
ginning of the fourth year.* 

The time of the appearance of the incisors and pre- 
molars has already been indicated in the preceding 
chapter. However, the following extract from Prof. 
Owen's "Odontography" is appropriate in this place, 
as it throws further light on the subject, and to some 
extent agrees with the dates already given : 

" The first true permanent molar appears between 
the eleventh and thirteenth months. The second fol- 

* For further particulars concerning the tushes the reader is 
referred to the succeeding chapter. 



56 THE PEHMAN^EKT DEKTITIO?^. 

lows between the fourteentli and twentieth months. 
The crowns of the premolars and the last true molar 
are now advancing in the closed sockets of reserve. 
The first premolar displaces the second,* and usually 
at the same time the very small deciduous molar, at 
from two years to two years and a half old. The first 
permanent incisor rises above the gum between two 
years and a half and three years. At the same period 
the second premolar pushes out the third deciduous 
molar. The last premolar displaces the last deciduous 
molar about the completion of the fourth year, and 
the appearance above the gum of the last true molar 
is usually anterior to this. The second incisor jDushes 
out its predecessor between three and a half and four 
years. The small persistent canine or tusk, contrary 
to the usual rule, next follows, its development having 
received no check by the retention of its rudimental 
predecessor. Its appearance indicates the age of four 
years ; but it sometimes appears earlier, rarely later. 
The third incisor pushes out the deciduous one about 
the fifth year, but is seldom completely in place before 
the horse is five years and a half old. The third pre- 
molars are then usually on a level with the other 
grinders." 

On the completion of the fifth year a male foal is 
called a horse, a female or filly foal a mare. The teeth, 
however, are not all fully developed before the sixth 
year, and the roots of the grinders do not begin to 

*To prevent confusion, it should be understood that Prof. 
Owen calls the "very small deciduous molar" here referred to 
the first deciduous molar, notwithstanding it is not functionally 
developed. Hence, as it has no successor, the first premolar dis- 
places the second deciduous molar, the second premolar the third 
deciduous molar, and the third the fourth. 



THE II'^CISORS ADAPTED FOR GRAZING. 



57 



grow till about the seventh year, being, to use Prof. 
Owen's words, "implanted in the socket by an undi- 
vided base." 

The incisor teeth, which will average about two 
inches and a quarter in length, are characterized by 
distinct curvatures, the outer sur- 
foce, according to Surgeon John 
Hughes, forming a third of a cir- 
cle, the inner a fifth. Were a string 
drawn from the crown of one of 
these teeth to the apex of the 
root, the figure would resemble a 
bow. The upper teeth are larger 
than the lower, and there is a dif- 
ference in size of the respective 
teeth in both jaws, the centrals 
being larger than the dividers, 
and the dividers larger than the 
corners. 

The incisors meet edge to edge, 
being thus admirably adapted for 
the purposes of srrazino^, and at 

. , „ . 1 . -, . -*■ ^JrKi" incisor tooth ; poS' 

the age oi six years the bodies are terior face.-cA<iOTea«. 
nearly perpendicular one to the other. They form 
nearly semicircular figures, and, when the mouth is 
closed, present a rounded outer surface. 

" The incisors," says Prof. Owen, "if found detached, 
recent or fossil, are distinguishable from those of the 
ruminants by their greater curvature, and from those 
of all other anim:ils by the fold of enamel which pen- 
etrates the body of the crown, from its broad, flat sum- 
mit, like the inverted finger of a glove." 

The fold oT enamel, which is commonly called the 
"mark," but which is also known as the infundibulum, 





58 THE PEEMAKENT DENTITION. 

central enamel, &c,, according to Surgeon J. Hughes^s 
measurements, penetrates the lower centrals to the 
depth of from | to -i\ of an inch ; the divid- 
ers from yV to f , and the corners from | to 
|. It penetrates the upper centrals from 1 
inch and ^V ^^ 1 ^^^ i 5 ^^^^ dividers from 
1 and ^ to 1 and J, and the corners from | 
to nearly 1 inch. Prof. Youatt says the 
grinders have each two infundibula, which 
penetrate to their roots. 

The following is Prof. A. Chauveau's description of 
the incisor teeth (" The Comparative Anatomy of the 
Domesticated Animals," Fleming's trans., p. 349) : 

" The general form of the incisors is that of a tri- 
faced pyramid, presenting an incurvation whose con- 
cavity is toward the mouth. Tlie base of this pyra- 
mid, the crown of the tooth, is flattened before and 
behind. The summit or extremity of the fang, is, on 
the contrary, depressed on both sides. The shaft of 
the pyramid presents at different points of its bight, a 
series of intermediate conformations, which are utilized 
as indications of age, the continual growth of the teeth 
bringing each of them in succession to the frictional 
surface of the crown. 

" Examined in a young tooth, but one that has com- 
pleted its evolution, the free portion presents the fol- 
lowing characteristics: An anterior face, indented by 
a slight longitudinal groove, which is prolonged to 
the root ; a posterior face, rounded from side to side; 
two borders, of which the internal is always thicker 
than the external ; and, lastly, the surface of friction. 
The latter does not exist in a tooth that has not been 
used, but in its stead are two sharp margins, circum- 



THE TWO IIIXGS OF EXAM EL. 59 

scribing a cavity named the external dental cavity, or, 
better, infundibuliim. This cavity terminates by a 
conical cul-de-sac, which descends more or less deeply 
into the substance of the tooth. The margins are 
designated the anterior and posterior. The latter, less 
elevated than the former, is cut by one or more 
notches, which are always deepest in the corner teeth. 
It is by the wear of these margins that the surface of 
friction is formed, and in the center of which the in- 
fundibulum persists during a certain period of time. 

^' The root is perforated by a single aperture, through 
which the pulp of the tooth penetrates into the inter- 
nal cavity. 

"In tlie composition of the incisor teeth are found 
the three fundamental substances of the dental organ. 
The dentine envelops the pulp cavity. Dentine is de- 
posited in this cavity after the complete evolution of 
the tooth to replace the atrophied pulp, the yellow tint 
of which distinguishes it from the dentine of the first 
formation. It forms on the table of the tooth the 
mark designated by Girard the dentinal star. 

" The enamel covers the dentine, not only on its free 
portion, but also on the roots; it does not extend, 
however, to their extremities. It is doubled into the 
external dental cavity, lining it throughout; and when 
the surface of friction is established, a ring of enamel 
may be seen surrounding it, and an internal ring cir- 
cumscribing the infundibulum. The first circle is 
called the encircling enamcU the second the central 
enamel. In the virgin tooth the central enamel is 
continuous with the external enamel, and passes over 
the border which circumscribes the entrance to the 
infundibulum, 

" The cement is applied over the enamel like a pro- 



60 THE PERMANEI^T DEIJTTITION. 

tecting varnish, but is not everywhere of the same 
thickness. On the salient portions it is extremely 
thin, and the friction caused by the food, the lips, and 
the tongue soon wears it away altogether. It is more 
abundant in depressed situations, as in the longitudi- 
nal groove on the anterior face of the tooth, and par- 
ticularly at the bottom of the infundibulum. The 
quantity accumulated in this cul-de-sac is not, how- 
ever, always the ^ame. We have seen it almost null, 
and on the other hand, we possess an incisor unworn, 
or nearly so, in which the cavity is almost entirely 
obstructed by it. We are not aware that, up to the 
present time, any account has been taken of these dif- 
ferences in calculating the progress of wear; but it is 
manifest that they shorten or prolong the time re- 
quired for the effacement of the infundibulum." 

The grinder teeth, the horse's millstones, present 
various and interesting contrasts. They are sepa- 
rated from the incisors by a space that will average 
about four inches in extent, the sharp-pointed tushes 
(in males) only intervening. The space between the 
grinders and tushes is called the diastema (place for 
the bit). The upper grinders, except the first and 
last, are nearly quadrangular in form. The first and 
last, which exceed the others about a third of an inch 
in antero-posterior (front to rear) diameter, terminate 
in obtuse angles, which are far more pronounced on 
the inner than on the outer surface, thus affording the 
tongue fuller and freer play, without the danger of its 
being lacerated, as would be the case were the angles 
sharp. The form of the lower grinders, with the same 
exceptions in the case of the first and last, is nearly 
rectangular; their antero-posterior diameter is the 



THE HORSE'S DINXER TABLES. CI 

same as that of the upper teeth, but their transverse 
diameter is nearly a half less. 

The broad crowns of the upper teeth form what are 
called by veterinarians "tables," whereon the food is 
ground or kneaded by the narrow-crowned opposite 
grinders, the lateral movement of the lower jaw ena- 
bling the latter teeth to pass over the entire extent of 
tlie former. 

The crown surfaces of the upper and lower rows are 
slanting instead of level, the former slanting inward, 
the latter outward. The inclined-planes are thus in 
perfect opposition, and yet in perfect harmony, for they 
facilitate the lateral and semicircular movement of the 
lower jaw during mastication. 

The figures formed by the upper and lower rows of 
grinders, aside from the difference in their thickness, 
are very dissimilar. The upper rows are slightly con- 
cave, and converge in conformity to the narrowing of 
the jaws; the space between the sixth grinders averages 
about two inches and four-fifths, while that between 
the first is about two inches. The lower rows form 
regular but oblique lines, which also converge, like the 
sides of a hopper, in conformity to the narrowing of 
the jaws, the space between the two sixth grinders and 
the two first averaging respectively two inches and a 
half and one inch and a half. Thus, when the mouth 
is closed, the lower teeth in the region of the sixth 
grinders scarcely cover a third of the crown surface of 
the upper teeth, while those in the region of the first 
barely lap their inner edges. This apparent structural 
defect is overcome by the lateral movement of the 
lower jaw, which, owing to the fact that it increases 
in proportion to the distance from its hinge-like joint 
in the region of the temporal bone and zygomatic 



62 THE PERMANEKT DENTITION. 

arch,* is greater in the region of the first grinders 
than in that of the sixth. Therefore it will be per- 
ceived that it is only alternately that the rows are used 
in the performance of the masticatory function, and 
that were the grinders in exact apposition (edge to 
edge), the lateral and semicircular movement of the 
lower jaw would be as awkward and unnatural in the 
case of the horse as the same movement would be. in a 
human being. 

There are still other contrasts between the grinders. 
According to Surgeons M. H. Bouley and P. B. Fergu- 
son, the upper teeth are slightly convex, the lower 
slightly concave. Again, according to Charles D. 
House, the outer surface of the upper grinders is pro- 
vided with a coat of enamel twice as thick as that of 
the inner, while the reverse is the case with the lower 
teeth. There is design in this provision of Nature 
(notwithstanding Mr, House says it is inexplicable), 
for the projecting edges receive that which they re- 
quire, to wit, strength in proportion to their bight; 
otherwise they would be easily broken off. As the 

* Prof. Youatt says: "The branclies of the lower jaw termi- 
nate in two processes, the coracoid (beak-like), and the condy- 
loid (rounded). The coracoid passes under the zyjromatic arch, 
the temporal muscle being inserted into it and wrapped round 
it. The condyloid is received into the glenoid (shallow) cavity 
of the temporal bone, at the base of the zygomatic arch, and 
forms the joint on which the lower jaw moves. The joint ad- 
mits of a hinge-like motion, which is the action of the jaw in 
nipping the herbage and seizing the corn. The corn, however, 
must be ground ; bruising and champing it are not sufficient for 
the purposes of digestion. It must be put into a mill. It is put 
into a mill, and as perfect a one as imagination can conceive. 
The construction of the glenoid cavity gives the required lateral 
or grinding motion. " 



THE GRIKDERS THEIR OWN WHETSTOKES. 



63 



lower edges have ouly about half the bight of the up- 
per, they do not require more than half the quantity 
of enamel to strengthen them. Another use of this 
unequal disposition of enamel is its tendency, by its 
wear, to preserve the slant of the -respective crown sur- 
faces. Further, the dentine, which fills the interspaces 
between the folds or ridges of enamel, being softer 
than the enamel, wears out faster, thus keeping the 
ridges sliarp.* The grinders are therefore, owing to 
this "interblending of the dental tissues," their own 
whetstones as well as the horse's millstones. 

Some writers, even of the present day, deny that the 
enamel penetrates to the interior of the grinders; but 
the faxjt that it does was established by John Hunter 
over a century ago, and a cut of a section of a horse's 
grinder (slightly magnified) showing the enamel folds, 

* Prof. R. Owen illustrates the above principle in the Intro- 
duction to his "Odontography." pagre 36. He says: "It (the 
enamel) sometimes forms only a partial investment of the crown, 
as in the molar teeth of the iguanodon, the canine teeth ot the 
hog and hippopotamus, and the incisors of the Rodentia. In 
these the enamel is placed only on the front of the tooth, but is 
continued along a great part of the invested base, which is never 
contracted into one or divided into more roots, so that the char- 
acter of the crown of the tooth is maintained throughout its 
extent as regards both its shape and structure. The partial 
application of the enamel operates in maintaining a sharp edge 
upon the exposed and worn end of the tooth precisely as the 
hard steel keeps up the outer cutting edge of the chisel by being 
welded ao-jiinst an inner plate of softer iron." 

Prof C^S Tomes, speaking of the grinder teeth of the horse, 
Bays • " As each ridge and pillar of the tooth consists of dentine 
bordered by enamel, and the arrangement of the ridges and pil- 
lars is complex, and as, moreover, cementum fills up the inter- 
spaces, it is ol5vious that an efficient rough grinding surface will 
be preserved by the unequal wear of the several tissues. ' 



64 THE PEllMANEIS^T DEKTITIOiN^. 

may be found in his "Natural History of the Human 
Teeth.'' 

The formation of the enamel is thus described by 
Prof. Bouley and Surgeon Ferguson ("Veterinarian," 
1844) : 

" In the grinder teeth the enamel may be said to 
resemble a little ribbon, which forms, in refolding 
many times upon itself in the interior of the tooth, a 
succession of undulating planes, and constitutes the 
hard external envelop of the cubic mass of the organ. 
An idea of this disposition may be formed on examin- 
ing a tooth which is not yet cut, but Avhich is ready to 
be cut. Those that have been worn, present on their 
crowns, besides the undulating lines of the enamel 
envelop, a sue session of reliefs, salient and sinuous, of 
the substance of the enamel, which are nothing else 
than the free borders of. this folded ribbon. It is in 
the intervals of the folds of enamel that is deposited 
the ivory-colored substance (dentine), which renders 
the tooth a solid mass when it has attained its full 
growth." 

Prof. Eichard Owen, one of the first odontologists 
of the age, in whose numerous works descriptions of 
many kinds of teeth may be found, has paid a fair 
share of attention to the study of horses' teeth, both 
recent and fossil. His description of the grinders and 
comparisons with the teeth of other animals are too 
interesting to be omitted here, and render any apology 
for the few repetitions of facts already given unneces- 
sary. He says (" Odontography," vol. i, p. 572) : 

"The horse will yield us the first example of the 
dentition of the hoofed quadrupeds with toes in un- 



ANOPLOTHERES, KUMINAXTS, AND TAPIRS. G5 

even number, because it oifers in this part of its organ- 
ization some transitional features between the dental 
characters of the typical members of the isoclactyle 
and of those of tlie anisodactyle ungulata. 

"All the kinds of teeth are retained and in almost 
normal numbers in both jaws, with as little unequal 
or excessive development as in the anojilothere,* but 
the prolongation of the slender jaws carries the canines 
and incisors to some distance from the grinders, and cre- 
ates a long diastema, as in the ruminants f and tapirs. J 

* " The anoplotliere was one of tlie earliest forms of hoofed 
quadrupeds introduced upon the surface of this earth, and it is 
characterized by the most complete system of dentition. It not 
only possessed incisors and canines in both jaws, but they were 
so equally developed that they formed one unbroken series with 
the premolars and molars, which character is now found only 
in the human species. The dental formula is : L, 3—3, 3—3 ; 
C, 1-1, 1-1; P.M., 4-4. 4-4; M., 3-3, 3-3=44. The An- 
oplothere Commune was the size of an ass, and, with the other 
species of the extinct g-enus, had a cloven hoof, like the Rumi- 
nants, but the division extended throujxh the metacarpus and 
metatarsus. The anoplothere was an animal of aquatic habits, 
and had a very long^ and strong tail, which Cuvier conjectures 
to have been used like that of the otter in swimming." — Oicen. 

f "The ordinary dental formula of the Ruminantia is : I. 
(upper jaw), 0-0, (lower jaw), 3—3 ; C. 0-0, 1-1 ; P. M., 3-3, 
3-3; M., 3-3, 3-3=32. The antelopes, the sheep, and the 
ox, which are collectively desiornated the 'hollow-horned ' rumi- 
nants, present this formula. It likewise characterizes many of 
the ' solid-horned ' ruminants, or the deer tribe, the exceptions 
having canine teeth in the upper jaw in the mal^ sex, and some- 
times also in the female, thougli they are always smaller in the 
latter." — Oucen. 

X " The dental formula of the tapir is : I., 3-3. 3-3 ; C. , 1—1, 
1-1 ; P. M., 4-3, 4-3 ; M., 3-3, 3-3=^42."— O^^cn. 

It is noteworthy that the dentition of the tapir corresponds 
precisaly in number with that of the horse^ provided the latter's 



66 THE PERMANENT DENTITION. 

" The upper grinder teeth present a modification of 
the complex structure intermediate between the ano- 
plotherian and ruminant patterns. The crown is 
cubical, but is impressed on the outer surface by two 
wide and deep longitudinal channels. It is penetrated 
from within by a valley, which enters obliquely from 
behind forward. This is crossed by two crescentic 
valleys, which soon become insulated, as in the camel;* 
but a large internal lobe, at the end of the oblique val- 
ley, presents more of the anoplotherian proportions 
than is shown by any ruminant. It is at first distinct; 
but although it soon becomes confluent with the ante- 
rior lobe in the existing species of the horse, it con- 
tinued distinct much longer, and with more of the con- 
ical or columnar form, in the primigenial horse of the 
miocene tertiary period. 

"The grinder teeth of the horse, Cuvierf remarks, 



Remnant teeth are counted ; and, besides, the odd teeth in both 
animals appear in the upper jaw. Prof. T. H. Huxley says : 
" Deepen the valley, increase the curvature of the (outer) wall 
and lam'inae (transverse ridges); give the latter a more directly 
backward slope ; cause them to develop accessory ridges and 
pillars, and the upper molars of the ta])ir will pass through the 
structure of that of the rhinoceros to that of the horse." 

■^"The dental formula of the camel is: I., 1 — 3, 1—3; M., 
6—6, 6—6=33. The anterior molars are conical. They are 
separated from the posterior molars, and are sometimes regarded 
as canines. The upper incisors are also conical, compressed, 
somewhat curved, resembling canines, and are used for tearing 
up the hard and strong plants of the desert, oii which the ani- 
mal usually feeds." — American Cyclopedia. 

\ A French naturalist. Died May 13, 1832. "He is regarded 
as the founder of the science of comparative anatomy, and his 
knowledge of the science was such that a bone or a small frag- 
ment of a fossil animal enabled him to determine the order, and 



THE HORSE AND THE RHINOCEROS. 67 

have a closer analogy with those of the rhinoceros* 
than might at first he supposed. The anterior cres- 
centic enamel represents the termination of the prin- 
cipal or oblique valley, which is cut off by a bridge of 
dentine analogous to that in the leptorhine rhinoceros. 
The posterior crescentic island is a further develop- 
ment of the folds in the rhinoceros' molar, but is much 
earher insulated in the horse. 

*-Tn the lower jaw the same analogies may be traced. 
The teeth, on tlie outer side, are divided into two 
convex lobes by a median longitudinal fissure; on the 
inner side they present three principal unequal convex 
ridges, and an anterior and posterior narrower ridge. 
The crown of the grinder is penetrated from the inner 
side by deeper and more complex folds than in the 
anoplothere, and still more so than in the rhinoceros 



even genus, to wliich it belonged. The time of Cnvier marks 
the ©lining of a new epoch in comparative anatomy. He ap- 
plied this science to natural history, physiology, and to the study 
of fossils The first edition of "Lemons d'Anatomie Comparee" 
appeared about the beginning of the present century, and the 
second was the last work upon which Cuvier labored. For 
more than thirty years he had collected an immense amount of 
facts and materials, which are partly embodied in this book. It 
is a monument of patient industry, a model in arrangement, and ^ 
a mine of knowledge, of which all observers since have availed 
themselves. " — American Cyclopedia. 

* " The essential characteristics of the dentition of the genua 
rhinoceros are to be found in the form and structure of the 
molar teeth. They differ essentially from those of the horse by 
being implanted by distinct roots. The normal dental formula 
of the molar series is: P. M.. 4-4, 4-4; M.. 3-8, 3-3=28. 
There are no canines. As to the incisors, the species vary, not 
only in regafd to their form and proportions, but also their ex- 
istence." — Owen. 



68 THE PEEMANElsTT DENTITION". 

and paleothere.* The anterior valley between the nar- 
row ridge and the first principal internal column ex- 
pands into a subcrescentic fold. The second is a short, 
simple fold, and terminates opposite that which pene- 
trates the tooth from the outer side. The third inner 
fold expands in the posterior lobe of the tooth like the 
first, and two short folds partially detach a small ac- 
cessory lobe at the posterior part of the crown. All 
the valleys, fissures, or folds, in both the upper and the 
lower grinders, are lined by enamel, which also coats 
the whole exterior surface of the crown. 

'^ The character by wdiich horses' grinders may best 
be distinguished from the teeth of other herbivora cor- 
responding with them in size, is the great length of 
the tooth before it divides into roots. This division, 
indeed, does not begin to take place until much of 
the crown has been worn away. Thus, except in old 
horses, a considerable proportion of the whole of the 
tooth is implanted in the socket by an undivided base. 
This is slightly curved in the upper grinders. 

"The deciduous molars have shorter bodies than the 
permanent, and sooner begin to develop roots. They 
may be distinguished from the rooted molar of a rumi- 
nant, as may also their permanent successors with 
roots, by their form and the pattern of their grinding 
surface. The latter may be a little changed by the 
partial obliteration of its enamel folds, but it gen- 
erally retains enough of its character to show the 
distinction." 

* " The species of paleotheriiim, which appear to have accom- 
panied the anoplotheres in the first introduction of hoofed quad- 
rupeds upon this planet, were characterized by the same com- 
plete dental formula, namely, forty-four functionally developed 

teeth," — Owen. 



ARISTOTLE'S MISTxVKE. 69 

Monsieur Lecoq's description of the grinder teeth, 
like the one just quoted, is a contribution to dental 
science. The repetition of facts already given is off- 
set by its additional facts, and its historical informa- 
tion is as interesting as are Prof. OAven's comparisons. 
It is as follows (" Traite de I'Exterieur du Cheval et des 
Principaux Animaux Domestiques*') : 

" It was believed for a long time that the grinders of 
Solipeds were all persistent teeth. This error, founded 
on the authority of Aristotle, was so deeply rooted that, 
aitliougli Ruini, toward the end of the Sixteenth ceri- 
tur}^, had discovered the existence of two temporary 
molars, Bourgelat did not believe it when he founded 
the French veterinary schools, and was only convinced 
when Tenon proved by specimens, in 1770, that the 
first three are deciduous. 

" Generally considered, the grinder arcades have not 
the same disposition in both jaws. Wider apart in the 
superior one, they form a slight curve, whose convexity 
is outward. In the inferior jaw, on the contrary, the 
two arcades separate in the form of a V toward the back 
of the moutii. Instead of coming in contact by level 
surfoces, the grinders meet by inclined-planes. In the 
lower jaw the internal border is higher than the exter- 
nal, while the reverse is the rule in the upper. This 
circumstance prevents the lateral movement of the 
lower jaw taking place without separation of the inci- 
801*8, and thus saves them from friction. 

" Like the incisors, each grinder presents for study 
a free and a fixed portion. The free portion (the body), 
nearly square in the upper grinders, broader than 
thick in th& lower, shows at the external surface of the 
former two longitudinal grooves, the anterior of wliich 



70 THE PERMAXEiq^T DEXTITIO^. 

is the deeper, both being continued on the incased 
portion. This is not the case with the lower grinders, 
which have but one narrow and frequently indistinct 
groove. The internal surface, in both jaws, presents 
only one groove, and that but littla marked. It is 
placed backward in the upper teeth, and is most ap- 
parent toward the root. "Xhe anterior and posterior 
faces of the respective teeth, which are in contact with 
each other, are nearly level, but at the extremities of 
the arcades the isolated faces are converted into a nar- 
row border. 

^' The grinders are separated from each other by their 
imbedded portion, particularly at the extremities of 
the arcades, an arrangement which strengthens them 
by throwing the strain put upon the terminal teeth 
toward the middle of the line. They exhibit a variety 
of roots. In the first and hist, either above or below, 
there are three, while the intermediate teeth have four 
in the upper jaw, and only two in the lower. The 
root, if examined a short time after the eruption of 
the free };)ortion, looks only like the shaft of the latter, 
without fangs,* but a wide internal cavity. The roots 
form when the teeth begin to be pushed from their 
sockets ; they cease to grow as soon as their cavities 
are filled with new dentine, but the tooth, constantly 
growing, causes the walls inclosing it to contract; so 
that in extreme age the shaft, completely worn away, 
leaves several stumps formed by the roots. 

" The replacement of the twelve molars is not at all 
like what happens with the incisors. They grow im- 

* Fang for root is obsolete. Fang signifies croz/^w— especially 
the pointed teetli of animals of prey and the poison-fang of ser- 
pents. Fang for both root and crown causes confusion. 



KELATLVE SIZE OF THE GlUinDERS. 71 

mediately below the temporary teeth, and diride their 
two roots iuto four, the uUorbiDg process continuing 
until the bodies axe reduced to simple plates and fall 
off." 

In measuring the teeth in a large-sized head the 
following facts and figures were elicited: Length of 
grinder rows, 7 inches. Space between the sixth 
grinders, upper rows, measuring from the inner sur- 
faces, but not including the angles, 3 inches; center of 
rows, 2ff ; first gi'inders, not including the space of 
the angles, 2^. Lower rows: Between the sixth 
grinders, 2|; center of rows, 1||; first grinders, 1^. 
Upper tush from first grinder, 2-} ; fi'om third incisor, 
1-J. Lower tush from grinder, 3^; from incisor, |. 
Space between the upper tushes, 2 ; between the lower, 
1|. Space between the upper corner incisors, measur- 
ing from center of teeth, 2 ; lower, l|f ; between the 
upper dividers, 1J-; lower, 1|. Distance around semi- 
circle of upper incisors, 4^; around lower, 34-|- 

As a supplement to the above, the following extract 
is made from '* An Essay on the Teeth " by Surgeon 
John Hughes (" Veterinarian/' 1841, "Proceedings 
Vet. Med. Ass.," p. 22): 

" The upper and lower grinders will measure from 
2| to 3 inches in length. In transverse diameter the 
former exceed the latter in the proportion of 7 to 4. 
The aggregate measurement of the sockets of the up- 
per grinders is about 7 inches. The first tooth occu- 
pies one inch and a half of this space, the second 1|^, 
the third 1^ the fourth 1, the fifth 1, and the sixth 1^. 
The bread tlf of the corresponding lower teeth is about 
the same as that of the upper." 



72 THE PERMAXEXT DEKTITIOI^. 

There is a difference iu the structure of all the teeth, 
and an expert can tell to which socket each belongs. 
Thev tit their sockets accurately,* are braced all round 
by the jawbone processes, and receive besides support 
and protection from the gums, which adhere to them 
tenaciously and are almost as hard as cartilage. Use 
and time, however, work changes, the teeth all wearing 
down, the incisors in particular changing shape and 
projecting outward. At the age of twelve years the 
gums begin to slacken, causing the teeth to look 
longer. The change from the upright position of the 
incisors, and the increased space between them and 
the canines, is caused by the elongation of the jaws, 
v\^hich carries the incisors outward. Tlie canines do 
not change their position, but they become mere stubs. 

* " The manner of attachment of the human teeth is that 
termed ' gomphosis,' i. e., an attachment comparable to the fit- 
ting of a peg into a hole. The bony sockets, however, allow of 
a considerable degree of motion, as may be seen by examining 
the teeth in a dried skull, the fitting being in the fresh state 
completed by the interposition of the dense periosteum of the 
socket. This latter, by its elasticity, allows of a small degree 
of motion in the tooth, and so doubtless diminishes the shock 
which would be occasioned by mastication were the teeth per- 
fectly immovable and without a yielding lining within their 
sockets." — C. S, Tomes, "Dental Anatomy," dx , p. 23. 

John Hunter says (" Human Teeth ") : " The roots of the 
teeth are fixed in the gum and alveolar processes by that species 
of articulation called gomphosis, which in some measure resem- 
bles a nail driven into a piece of wood. They are not, however, 
firmly united with the processes, for every tooth has S"me de- 
gree of motion; and in heads which have been boiled or macer- 
ated in water, so as to destroy the periosteum and adhesion of 
the teeth, we find them so loosely connected with their sockets 
that the incisors are ready to drop out, the grinders remaining, 
aa it were, hooked, from the number and shape of their roots. " 



THE HORSE AS A MILLER. 73 

Notwithstanding^ all these chani^-es it is a rare thing to 
see a missing incisor or grinder. The canines, how- 
ever, owing perhaps to their sharp points, not only 
WTar out, but now and then, in extreme old age, fall 
out. 

The permanent teeth agree with the temporary in 
but few respects, though the general appearance of the 
respective teeth is nearly the same. They differ in 
many respects. Their bodies are larger and denser, 
and their roots longer and stronger. The grooving of 
the incisors is the reverse; the outer surface is usually 
double grooved, the inner smooth, both being slightly 
rounded. They are less upright in position, and less 
sharp, but are more discolored, and tlie "marks" (in- 
fundibula) are wider and deeper and wear out more 
slowly. They attain their grow^th more slowly, and a 
healthy tooth continues to grow throughout life. 

In proof of the last assertion many authorities could 
be cited, but those that follow must suffice. It is a 
wise provision of Nature, as but for it a horse's teeth, 
particularly the grinders, would be worn to stubs in 
two or three years after their development. Prof. 
M. H. Bouley and Surgeon P. B. Ferguson say (" Vet- 
erinarian," 1844) : 

"The growth throughout life is a compensation for 
the enormous wear of the teeth, the horse having to 
perform for himself tliat which the miller performs for 
man ; and thus during a very long time the teeth pre- 
serve, if not their form, at least their length." 

Prof. A. Chauveau, referring to the horse, says: 

" The permanent teeth present in their development 
a common but very remarkable characteristic, rarely 
4 




74 THE PERilAXEXT DEXTlTIOi^. 

met with in other animals. They are thrust up from 
the alveoli during the entire life of the animal to re- 
place the surface worn by friction." 

The activity of the growth of the grinders is re- 
markable about the seventh year, for at this time 
their roots begin to develop ; growth is thus going on 
at both ends at the same time. A 
third movement is now at least 
apparent, for the undi^dded base 
in the socket appears to be slowly 
pushed out, which may partly ac- 
count for the shrinkage of the 
gums. The tenacity of the adhe- Left uppeTmoiar. 
sion of the periosteum would not wholly prevent this 
movement, for it acts as a cushion, its elasticity pre- 
venting concussions. The undivided base resembles 
a post set in the ground, except that the implanted 
part is smaller than the crown. 

Up to about the sixteenth year, the growth of the 
teeth results chiefly from vitality transmitted through 
the medium of the pulp. After the pulp has become 
converted into dentine, however, the tooth " draws its 
nourishment from the blood-vessels of the socket."* 

Surgeon Louis Brandt (" The Age of Horses," In- 
dianola, Texas, 1860) says of the incisors : 

^^ The length of the teeth is constantly decreasing, 
and often quite regularly, so that in extreme old age 
they will sometimes not exceed half an inch in length, 
while at their prime they were 2|^ to 3 inches long. 
Their breadth decreases nearly in proportion to the 
decrease in length." 

'^ See pages 169-70. 



CHAPTER IV. 

THE CANIXE TEETH OR TUSHES. 

Practically Useless. — Different in their Nature from the other 
Teeth. — Were they formerly Weapons of Offense and De- 
fense? — Views of Messrs. Darwin, Hunter, Bell, Youatt, and 
Winter. — Their time of Cutting the most Critical Period of 
the Horse's Life. 

The Canine Teeth {laniarii denies), comparatively 
speaking, are of little practical use; at least they are 
of little use to the modern horse. They have beeu 
much reduced in size during the evolution of the horse, 
and, if Mr. C. R. Darwin's theory is correct, are prob- 
ably "in the course of ultimate extinction." They 
distinguish the sex, it is true, but their loss would not 
be felt on that account. The horse sometimes uses 
them in tearing bark from trees, for he is by instinct 
his own (botanical) doctor, and the bark is his medi- 
cine. The sharp points of the tushes penetrate the 
bark more readily than the incisors, and apparently 
the horse wishes to save his incisors, thus showing his 
horso-sense. Their nature is different from that of 
the other teeth, for the incisors and grinders grow till 
old age. This is not the case with the tushes, and, 
further, they are never in apposition (superposed), and 
consequently do not wear one another. 

The lower tushes, as before said, are about three- 
fourths of an inch from the corner incisors, and abont 
three inches and a half from the tirst grinders. The 



76 THE CAXIKE TEETH. 

space between tlie upper tuslies and the corner incisors 
is double that of the lower, and thejare consequently 
three-fourths of an inch nearer the grinders. The dis- 
tances may vary a half an inch or more. The space 
between the tushes and grinders is, as already said, 
called the diastema. 

The average hight of the tushes when full grown is 
about three-fourths of an inch. They resemble tri- 
angles, having broad bases and sharp crowns, the latter 
being remarkable, says Prof Owen, "for the folding in 
of the anterior and posterior margins of enamel, which 
here includes an extremely thin layer of dentine." 
They have a slight outward inclination, that of the 
lower teeth exceeding that of the upper. Their outer 
surface is oval, the inner (in the young horse) being 
deeply grooved. As age advances the inner surface 
becomes oval also, and the crowns more or less blunt. 
The root of a tush, which is longer than its body, 
has a distinct backward curvature, rendering the ex- 
traction of these teeth almost impossible. The tushes 
have no "marks" (infundibula), the nerve cavity ex- 
tending through nearly the entire length of the tooth. 

Monsieur Lecoq says : 

"The free portion of the tusk, slightly curved and 
thrown outward, particularly in the lower jaw, presents 
two fLices (internal and external), separated from one 
another by two sharp borders, which incline to the 
inner side, and meet in a point at the extremity of the 
tooth. The external face, slightly rounded, presents a 
series of fine strise, longitudinal and parallel. The 
internal has a conical eminence in its middle, whose 
point is directed toward that of the tooth, and is sep- 
arated from each border by a deep groove. 



SIMPLICITY OF THEIR STRUCTURE. 77 

*•' The root of the tusk, more curved than the free 
portion, bears internally a cavity analogous to that of 
the root of tlie incisors, and, like it, diminishes in size 
and finally disappears as age advances; but it is always 
relatively larger, because of the absence of the infun- 
dibuluni in the canine teeth. 

" The structure of these teeth is much simpler than 
that of the incisors, consisting, as they do, of a central 
mass of dentine, hollowed by the pulp cavity, and cov- 
ered by an external layer of enamel, on which is de- 
posited a little cement." 

As there is more or less mystery about the tushes, 
and as they are important factors in the consideration 
of tilt? problem of the evolution of the horse as well as 
other animals, a few extracts from the works of well- 
known scientific men, giving their views on the sub- 
ject, will prove interesting if not instructive. 

Mr. Charles E. Darwin gives the following interest- 
ing account of tushes and their uses in certain animals, 
among them the horse (" Descent of Man," vol. ii, pp. 
245-G-:) : 

" Male quadrupeds Avhich are furnished with tusks 
use them in various ways, as in the case of horns. 
The boar strikes laterally and upward, the musk-deer 
with serious effect downward. The walrus, though 
having a short neck and unwieldy body, 'can strike 
upward, downward, or sideways Avith equal dexterity.' 
The Indian elephant fights, as I was informed by the 
late Dr. Falconer, in a different manner according to 
the position and curvature of his tusks. When they 
are directed forward and upward, he is able to fling a 
tiger to a great distance — it is said to even thirty feet; 



78 THE CANINE TEETH. 

when they are short and turned downward, he en- 
deavors suddenly to pin the tiger to the ground, and 
in consequence is daugerous to the rider, who is liable 
to be dismounted. 

*• Very few male quadrupeds possess weapons of two 
distinct kinds specially adapted for lighting with rival 
males. The male muntjac-deer {Cervuh(s), however, 
offers an exception, as he is provided with liorns and 
exserted canine teeth. But one form of weapon has 
often been replaced in the course of ages by another 
form, as we may infer from what follows. With rumi- 
nants the development of horns generally stands in an 
inverse relation with that of even moderately well- 
developed canine teeth. Thus camels, guanacoes, 
chevrotains, and musk-deer are hornless, and they 
have efficient canines, these teeth being 'always of 
smaller size in the females than in the males.' Male 
deer and antelopes, on the other hand, possess horns, 
and they rarely have canine teeth, and these when 
present are always of smaller size, so that it is doubt- 
ful whether they are of any service in their battles. 
With Antelope montana they exist only as rudiments 
in the young male, disappearing as he grows old. 
Stallions have small canine teeth, bnt they do not 
appear to be used in fighting, for stallions bite with 
their incisors, and do not open their mouths widely 
like camels and guanacoes. Whenever the adult male 
possesses canines now in an inefficient state, while the 
female has either none or mere rudiments, we may 
conclude that the early male progenitor of the species 
was provided with efficient canines, which had been 
partially transferred to the females. The reduction of 
these teeth in the males seems to have followed from 
some change in their manner of fighting, often caused 



TCSHES TEX FEET LOI^G. 79 

(but not in the case of the horse) by tlie development 
of new weapons." 

In the first volume of the "Descent of Man," page 
139, Mr. Darwin attributes the reduction in size of the 
tushes in horses to their " habit of fighting- with their 
incisor teeth and hoofs," and on page 231, of the sec- 
ond volume, he continues the discussion of canines in 
diS'erent animals as follows: 

" In the male dugong the upper incisors form offen- 
sive weapons. In the male narwhal one of the upper 
teeth is developed into the well-known, spirally-twisted, 
so-called horn, which is sometimes from nine to ten 
feet long. It is beheved that the males use these horns 
for lighting together, for ^an unbroken one can hardly 
be got, and occasionally one may be found with the 
point of another jammed into the broken place.' The 
tooth on the opposite side of the head in the male con- 
sists of a rudiment about ten inches in length, which 
is imbedded in the jaw. It is not, however, very un- 
common to find double-horned male narwhals in which 
both teeth are well developed. In the females both 
teeth are rudimentary. The male cach'alot* has a 

* " Sperm-whale or cachalot {Physeter macrocephalus). My 
friend Mr. Broderip possesses a tooth of a male Physeter, with 
the base open and uncontracted, which measures nine inches 
and a half in length, nine inches in circumference, and weighs 
three pounds. An ingenious whale-fisher has carved the chief 
incidents of his exciting and dangerous occupation on one side 
of this very fine tooth. The other side bears the following in- 
scription : ' The tooth of a sperm-whale, that was caught by the 
ship Adam's crew, off Albemarhj Point, and made 100 bbls. of oil, 
in the year 1817.' Below the inscription arc two exct'llcnt 
figures of the cachalot, one spouting, the other dead and marked 
for flensing."— O^rg/i's ''Odontography,'' Vol. /, j)p 353-4. 



80 THE cA:Nri:N'£ teeth. 

larger head than the female, and it no doubt aids these 
animals in their aquatic battles. Lastly, the adult 
male ornithorhyn'chus is provided with a remarkable 
apparatus, namely, a spur on the foreleg, closely re- 
sembling the poison fang of a venomous snake. Its 
use is not known, but we may suspect it serves as a 
weapon of oifense. It is represented by a mere rudi- 
ment in the female." * 

The foregoing extracts would not be complete with- 
out giving the views of this great disciple of evolution 
concerning the same teeth in man. He says (" Descent 
of Man," vol. i, p. 198) : 

" We have thus far endeavored rudely to trace the 
genealogy of the vertebrata by the aid of their mutual 
affinities. AVe will now look to man as he exists, and 
we shall, I think, be able partially to restore during 
successive periods, but not in due order of time, the 
structure of our early progenitors. This can be effected 
by means of the rudiments which man still retains, by 
the characters which occasionally make their appear- 
ance in him through reversion,! and by the aid of the 
principles of morphology and embryology. J; The early 

* For further information concerning this strange animal sea 
the " Vocabulary." 

f " The occasional appearance at the present day of canine 
teeth which project above the others, with traces of a diastema 
or open space for the reception of the opposite canines, is in all 
probability a case of reversion to a former state, when the pro- 
genitors of man were provided with these weapons." — ''Descent 
of 3L in:' Vol. II, p. 300. 

X " The human em'bryo resembles in various points of struc- 
ture certain low forms when adult. For instance, the heart at 
first exists as a simple pulsotinc^ vessel ; the excreta are voided 
through a cloacal passage, and the os coccyx projects like a true 



THE EARLY rROGLXITORS OF MAN. 81 

progenitors of man were no (loul)t once covered with 
hair, both sexes having beards. Their ears were 
pointed and capable of movement, and their bodies 
were provided with a taU, having the proper muscles. 
Their Ihnbs and bodies Avere also acted on by muscles 
which now only occasionally reappear, but are normally 
present in the quadrumana. The great artery and 



tail, 'extending considerably beyond the rudimentaTy legs.* 
The great-toe, as Prof. Owen remarks, 'which forms the ful- 
crum when standing or walking, is perhaps tlie most character- 
istic peculiarity in the human structure ;' but in an embryo 
about an inch in length. Prof. Wyman found that the great-toe 
was shorter than the others, and instead of being parallel to 
them, ' projected at an angle from the side of the foot, thus cor- 
responding with the permanent condition of this part in the 
quadrumana.' * * * When the extremities are developed, 
' the feet of lizards and mammals, the wings and feet of birds, 
no less than the hands and feet of man, all arise from the same 
fundamental form.' (Von Baer)." — "Descent of Man," Vol. I, pp. 
U-16. 

"Each human individual is developed from an egg, and this- 
GQ^ is a simple cell, like that of any animal or plant. The em- 
bryo, in the early stages of development, is not at all different 
from those of other animals. At a certain period it has essen- 
tially the anatomical structure of a lancelet (the lowest verte- 
brate), later of a fish, and in subsequent stages those of am- 
phibian and mammal forms. In the further evolution of these 
mammal forms, those first appear which stand lowest in the 
series, namely, forms allied to beaked animals (ornithorliyn- 
chus) ; then those allied to pouched animals (marsupials), which 
are followed by forms most resembling apes, till at last the 
peculiar human form is produced as the final result. Every one 
knows that the butterfly proceeds from a pupa, the pupa from a 
caterpillar, to which it bears no resemblance, and again the cat- 
erpillar from the Q^,g of the butterfly. But few, except those of 
the medioal profession, are aware that man, in the course of his 
individual evolution, passes through a series of transformations 



82 THE CAXINE TEETH. 

nerre of the hiimenis ran through a snpra-condyloid 
fora'men. At this or some earlier period the intestine 
gave forth a much larger diverticalum or ceecum than 
that now existing. The foot, judging from the con- 
dition of the great-toe in the fetus, was then prehen- 
sile, and our early progenitors were no doubt arboreal 
in their liabits, frequenting some warm, forest-clad 
land. The males were provided with great canine 
teeth, which served them as foinnidable weapons."* 

no less astonishing and remarkable than the well known meta- 
morphoses of the butterfly, * * * An examination of the 
human embryo in tlie third or fourth week of its evolution 
shows it to be altogether different from the fully developed 
man, and that it exactly corresponds to the undeveloped em- 
bryo-form presented by the ape, the dog, the rabbit, the horse, 
and other mammals, at the same stage of their ontog'eny (germ 
history), which may be demonstrated by placing the respective 
embryos side by side. At this stage it is a bean-shaped body of 
very simple structure, with a tail behind, and two pairs of pad- 
dles, resembling the fins of fish, and totally dissimilar at the 
sides to the limbs of man and other mammals. Nearly the 
whole of the front half of the body consists of a shapeless head, 
without a face, on the sides of which are seen gill-fissures and 
gill-arches, as in fishes. * * * The human embryo passes 
through a stage in which it possesses no head, no brain, no 
skull ; in which the trunk is still entirely simple and undivided 
into head, neck, breast, and abdomen, and in which there is no 
trace of arms or legs."— Ernst Heinrich Haeckel, "The Ecolution 
of Man;' Vol. I, pp. 3, 18, 253. 

* Mr. Darwin continues : " At a much earlier time the uterus 
was double ; the excreta were voided through a cloaca, and the 
eye was protected by a third eyelid or nictitating membrane. 
At a still earlier period the progenitors of man must have been 
aquatic in their habits, for morphology plainly tells ns that our 
lungs consist of a modified swim-bladder, which once served as 
a float. The clefts on the neck in the embryo of man show 
where the branchiae once existed," &c.,&c. 



DARWIX ONLY COKUOBOUATES IlLXTER. 83 

Agaiu, on page 138 of the same volame, Mr. Darwin 
says : 

'•The early progenitors of man were, as previously 
stated, probably furnished with great canine teeth ; but 
as they gradually acquired the habit of using stones, 
clubs, or other weapons for fighting witli'their enemies, 
they would have used their jaws and teeth less and 
less. In this case the jaws and the teeth would have 
become reduced iu size, as we may feel sure from nu- 
merous analogous cases."* 

*Dr. John Hunter, writing nearly one hundred years 
before Mr. Darwin's time, says (" The Human Teeth," 
p. 29). 

" The use of the cuspidati would seem to be to lay 
hold of substances, perhaps even living animals. They 
are not formed for dividing, as the incisors are, nor 
are they fit for grinding. We may trace in these teeth 
a similarity in shape, situation, and use, from the most 
imperfectly carnivorous animal— which we beheve to 
be the human species— to the most perfectly carnivo- 
rous, namely, the hon." 

The editor of Dr. Hunter's work, Mr. Thomas Bell, 
F.R.S., comments as follows on the above extract: 

"That our conclusions as to the functions of an 
organ as it exists in man, when drawn exclusively from 
analogous structures in the lower animals, will fre- 

*"The jaws, tofjetlier with their muscles, would then have 
become reduced throuprh disuse, as would the teeth, throucrh the 
not well understood principles of correlation and the economy of 
growth ; for \f e everywhere see that parts which are no longei 
of service are reduced in size." — ''Descent of Mdii." 



84 THE CA]S'I>s^E TEETH. 

quently prove erroneous, is strikingly shown in these 
observations on the use of the cuspidatus. The simple 
and obvious use of this tooth, in the human species, is 
to tear such portions of food as are too liard or tough 
to be divided by tlie incisors; and we frequently find 
it far more developed in animals which are known to 
be exclusively frugivorous. Not only is its structure 
wiiolly unadapted for such an object as that assigned 
to it in the text, but there is no analogous or other 
ground for supposing that man was originally con- 
structed for the pursuit and capture of living prey. 
His naturally erect position and the structure of the 
mouth would render this impossible by the means in- 
ferred by Hunter; and the possession of so perfect an 
instrument as the hand obviates the necessity of his 
ever employing any other organ for the purpose of 
seizing or holding food of whatever description." 

Prof. WiUiam Youatt says ('^The Horse," p. 22G): 

" At the age now under consideration (the fourth 
year) the tushes are almost peculiar to the horse, and 
castration does not appear to prevent or retard their 
development. All mares, however, have the germs of 
them in the chambers of the jaws, and they appear 
externally in the majority of old mares. Their use is 
not evident. Perhaps in the wild state of the horse 
they are weapons of offense, and he is enabled by 
them to more firmly seize and more deeply wound his 
enemy."* 

* Prof. C. S. Tomes says : " In the domestic races the tusks of 
boars are much smaller than in the wild animal, and it is a curi- 
ous fact that in domestic races which have become wild, the 
tusks increase in size at the same time that the bristles become 
more pronounced. Mr. Darwin suggests that the renewed 



THEIR PnySIOLOGICAL RELATIONS. 85 

Surgeon J. H. Winter, the author of a work entitled 
"On the Horse," says : 

" It is difficult to assign their use. Their position 
precludes the possibility of their being used as weapons 
of offense or defense. They may be viewed as a link 
of uniformity so commonly traced in the animated 
world." 

Prof. William Percivall says that the cutting of the 
tushes causes the constitution more derangement than 
all the other teeth, and Prof. Youatt and other high 
authorities entertain similar views. The present chap- 
ter, therefore, is a proper one in which to discuss " the 
effects of dentition on the system generally." The 
discussion of the subject is left to well-known men. 
Messrs. Youatt and Percivall were many years ago the 
editors of "The Veterinarian," but their books are 
probably the best monuments to their memory. Prof. 
William Williams is the President of the Edinburgh 
Veterinary College. Prof. Youatt says (" The Horse," 
p. 230) : 

" This is the proper place to speak of the effect of 
dentition on the system generally. Horsemen in gen- 
eral think too lightly of it, and they scarcely dream of 
the animal suffering to any considerable degree, or 

growth of the teeth may perliaps be accounted for on the prin- 
ciple of correlation of growth, external agencies acting on the 
skin, and so indirectly influencing the teeth." 

A strictly analogous result might or might not follow in the 
case of the horse. If so, the tushes would probably be used as 
weapons of offense and defense. It is reasonable to suppose that 
they were so used by the early progenitors of the horse, whose 
large tushes aje described in the succeeding chapter by Pro£ 
Marsh. 



80 THE CAXIXE TEETH. 

absolute illness being produced. Yet he who has to 
do with young horses will occasionally discover a con- 
siderable degree of febrile affection which he can refer 
to this cause alone. Fever, cough, catarrhal and cuta- 
neous affections, diseases of the eyes, diarrhea, dysen- 
tery, loss of appetite, and general derangement will 
frequently be traced to irritation from teething.* It is 
a rule scarcely admitting of the slightest deviation, 
that, when young horses are laboring under febrile 
affection, the mouth should be examined, and if the 
tushes are jDrominent and pushing against the gums, a 
crucial incision should be made over them."* 

Prof. Percivall says (" Hippopathology," vol. ii, p. 
225) : 

"There was a time when I treated the subject of 
dentition so lightly as to think that horses never suf- 
fered from such a cause. Experience, however, has 
altered my opinion. I now frequently discover young 
horses with disorders or febrile irritations the produc- 
tion of wi]ich I hesitate not to ascribe to teething. 
Many years ago I was consulted concerning a horse 
which had fed sparingly for a fortnight and lost rap- 
idly in condition. His owner, a veterinary surgeon, 
was apprehensive about his life. Another surgeon was 
of opinion that the ^cuddiug' arose from preternatural 

* Prof. Youatt's real sentiments are doubtless here expressed, 
but, unfortunately for bis consistency, on page 327 of the same 
"work, in speaking of tbe derangement caused by teething in 
children and dogs, he says: " The horse appears to feel little 
inconvenience. The gums and palate are occasionally some- 
what hot and swollen, but the slightest scarification will remove 
this." Perhaps Prof. Youatt, like Prof. Percivall, changed his 
opinion late in life, and neglected to remove the blemish from 
Lis book. 



WHAT CHANGED PROF. PERC IV ALL'S MIXD. 87 

bluntness of the molar teeth, which were filed. It 
was after this that I saw^ the horse, and I mast confess 
I was sit first quite as much at a loss to offer a satisfac- 
tory interpretation of the case as others had been. 
While meditating, however, after my inspection of the 
horse, on the apparently extraordinary nature of the 
case, it struck me that I had not seen the tushes. I 
went back into the stable and discovered two little 
tumors, red and hard, in the situation of the inferior 
tusks, which, when pressed, gave the animal insuffer- 
able pain. I instantly took out my pocket-knife and 
made crucial incisions tiirough them both, from which 
moment the horse recovered his appetite, and by de- 
grees his wonted condition. This case was the turn- 
ing point in my practice, and caused me to look more 
closely into dentition. 

" The cutting of the tushes, which may be likened 
to the eye-teeth of children, costs the constitution 
more derangement than all the other teeth put to- 
gether; on which account, no doubt, it is that the 
period from the fourth to the fifth 5*ear proves so crit- 
ical to the horse. Any disease, pulmonary in particu- 
lar, setting in at this period, is doubly dangerous. In 
fact, teething is one cause of the fatality among young 
horses at this period. 

" D'Arboval tells us to observe how the vital energy 
becomes augmented about the head, and upon the 
mucous surfaces in particular. He says: ^A local 
fever originates in the alveolar cavities. The gums 
become stretched from the pressure of the teeth against 
them. They dilate, sometimes split, and are red, hot, 
and painful. The roots compress the dental nerves 
and irritate the periosteal linings of the alveolar cavi- 
ties. These causes will enable us to explain many 



88 THE CAXIXE TEETH. 

morbid phenomena in horses about this, the most crit- 
ical period of their lives.' 

" When yoting horses are brought to me now for 
treatment/' continues Prof. Percivall, "I invariably 
examine the teeth. Should the tusks be pushing 
against the gums, I let them through by incisions 
over their summits, and 1 extract any of the tempo- 
rary teeth that appear to be obstructing the growth of 
the permanent. In this way I feel assured I have seen 
catarrhal and bronchial inflammations abated, coughs 
relieved, lymphatic and other glandular tumors about 
the head reduced, cutaneous eruptions got rid of, de- 
ranged bowels and urinary organs restored, appetite 
returned, and lost condition repaired. 

"I am quite sure too little attention has been paid 
to the teeth in the treatment of young horses, and I 
would counsel those who have such charges by no 
means to disregard this remark, trifling as it may 
appear. The pathognomonic symptoms calling our 
attention, whether in young or old horses, if not to 
the teeth themselves, to the mouth in general, are 
large discharges of saliva from the mouth, with occa- 
sional slobbering; cudding of the food; difficulty of 
mastication or deglutition, or both, and stench of buc- 
cal secretion, perhaps of the breath as well." 

Prof. Percivall continues the discussion of the sub- 
ject of dentition and its eff'ect on the health of the 
horse, dwelling more particularly on the disorder 
known as lanipas. He sa3^s: 

"There is connected with dentition another pecu- 
liarity in the horse which we must not allow to pass 
unnoticed. Although the period of teething, properly 



LAMPAS CAUSED BY TEETHIXG. 89 

speaking, may be said to terminate at the fiffh year, 
yet we must recollect it lias been satisfactorily demon- 
strated that there is a process of growth going on in 
the teeth throughout the remaiuder of life ; so that, in 
fact, at no period may the animal be said to be free 
from the influence of dentition. This accounts for 
lampas occurring in old as well as young horses, and 
furnishes my mind with strong proof that the tumidity 
of the bars of the mouth is dependent on operations 
going on in the teeth, and on that cause alone. 

" What we nowadays understand by lampas is an 
unnatural prominence or tumidity of the cai'tiluginous 
bars forming tlie roof of the mouth. Xaturally, tlie 
bars are pale-colored, whereas in a mouth affected with 
lampas they become red and tumid, losing their eir- 
cumllecture, and swelling to a level with the crowns of 
the incisor teeth, and in some cases even beyond them. 
This apparent augmentation of substance is ascribable 
to congestion of blood-vessels, but not to that alone. 
I believe that in many cases there will be found to be 
some serous and albuminous infiltration into the cel- 
lular membrane attaching the Imrs to the hard palate, 
and that this will account for the length of time the 
swelhng sometimes continues, as well as for the little 
relief, in regard to their diminution, which in such 
cases attends lancing of the gums. 

"Although in young horses it is, I believe, admitted 
that lampas is caused by the cutting of the teeth, yet 
in old horses there are those who ascribe its produc- 
tion to other causes, and imagine it has a great deal to 
do Avith a horse's health, or rather Avith his feeding. 
That lampas may in some cases be the cause of tender- 
ness in mastication, I do not deny; but, at the same 
time, I think I may safely aflEirm that in nine cases out 



90 THE CANIKE TEETH. " 

of ten the cause of loss of appetite will be found else- 
where. The reason why lampas appears in aged horses 
is, in my opinioUj as before stated, on account of the 
continuance of the process of growth in the teeth 
throughout life, with the nature and laws of which we 
are, in our present state of knowledge, too little ac- 
quainted to pretend to say why it should exist in one 
horse and not in another, or why it should only at 
times appear in the same horse. 

"Is lampas a disease? The complaints which daily 
reach our ears persuade us it is. Every groom having 
an un thriving horse, or one that does not feed, is sure 
to search for lampas. If he finds it, in his mind the 
cause of lack of thrift is detected, and the remedy 
obvious — burning. Many a horse has been subjected 
to this torturing operation, and has thereby got added 
to his other ailments a foul, sloughy, carious sore on 
the roof of his mouth. 

" Supposing that lampas be owing to the teeth, do 
not the teeth require removal, and not the bars of the 
mouth? In cutting or burning away lampas we mis- 
take the effect for the cause. If lampas is not produced 
by the irritation of teething, then I would like to be 
informed what does cause it." 

Prof. Youatt says of lampas (" The Horse," p. 219) : 

"It may arise from inflammation of the gums, 
propagated to the bars when the colt is shedding his 
teeth — young horses being more subject to it than 
others — or from some febrile tendency in the consti- 
tution generally, as when a young horse has lately 
been taken from grass, and has been over-fed or insuf- 
ficiently exercised. It is well to examine the grinders, 



MASHES AND LANCIIn"G RECOMMENDED. 91 

and more particularly the tushes, in order to ascertain 
whether they are nuiking their way through the gums. 
If so, incisions should be made across the swollen 
gums, and immediate relief will follow. At times it 
appears in aged horses, the process of growth in the 
teeth of the horse continuing during life. 

^^ The brutal custom of famers, who sear and burn 
the bars with a red hot iron, is most objectionable. It 
is torturing the horse to no purpose, and may do seri- 
ous injury. In a majority of cases the swelling will 
subside without medical treatment. A few mashes 
and gentle alteratives will give relief, but sometimes 
slight incisions across the bars with a lancet or pen- 
knife may be necessary. Indeed, scarification of the 
bars in lampas will seldom do harm, though it is not 
as necessary as is generally supposed.'^ 

Concerning "Diseases occurring during Dentition" 
Prof. AVilliam Williams says (•' Principles and Practice 
of Veterinary Surgery," p. 476): 

"In the horse the temporary grinders are replaced 
by permanent ones when he is from three to four years 
old, and in the ox at from two years and six months 
to two years and nine months. In cattle tlie cutting 
of the permanent molars is occasionally a matter of 
some difficulty owing to the unshed crowns of the 
temporary teeth becoming entangled with the new 
teeth, and thus proving a source of irritation and pre- 
venting the animal from feeding. In some parts of 
tlie country such animals are called * rotten,' from their 
emaciated condition, and perhaps from the fetor ema- 
nating from the mouth. When cattle of this age stop 
feeding, lose condition, or drivel froni the mouth, the 



92 : THE CAXINE TEETH. 

teeth should be examined, and if the unshed molars 
are causing irritation, they should be removed with 
the forceps. Hundreds of young cattle have been sac- 
rificed from this cause — actually dying of starvation. 
In the horse the same condition of the grinders may 
exist, but it is very unusual. The corner incisors, 
however, may present the same anomalous condition. 
Horses from four years to four years and six months 
old should have their teeth examined occasionally to 
see if all is going on well. 

" Horses at four years old are subject to a distressing 
cough. At this age the third temporary grinder is 
replaced by its permanent successor, and at the same 
time the sixth grinder is being cut. Some irritation 
exists in the gums during the eruption of all the teeth, 
and in some instances it is excessive, extending from 
the gums to the fauces and larynx. This is particu- 
larly the case with the sixth grinder, and as a result of 
the extension of the irritation, cough is excited, usually 
in the morning, when the animal begins to feed. It 
is loud, sonorous, and prolonged, the horse frequently 
coughing twenty, thirty, or even forty times without 
ceasing. It is a throat cough, originating in laryngeal 
irritation. 

" The treatment for this, which may be truly said to 
be a tooth-cough, is careful dieting on crushed food; 
hay, not much bran ; grass, if in season, or roots if 
grass is not obtainable ; alkaline medicines, more par- 
ticularly the bicarbonate of soda; gentle aperients 
occasionally, if the bowels be irregular. If the faeces 
are fetid the fetor will be much diminished by a few 
doses of the hyposulphite of soda, the mouth to be gar- 
gled with some cooling mixture, such as the borate of 
soda or alum." 



DE^'TIT10^' FEVEK. 93 

Of "Dentition Fever" Prof. Williams says ("Prin- 
ciples and Practice of Veterinary Surgery," p. 479) : 

" Horses from three to four years old are more sub- 
ject to this species of dental irritation than those of a 
more tender age, and it is well known among horsemen 
that they will stand more fatigue at a more tender age 
than they will at this. The reason is because teething 
is now at the hight of its activity. When the animal 
is three years -old, eight permanent grinders are being 
cut, and four permanent incisors are in active growth 
witlim the jaws. At four years of age the same num- 
ber of grinders are out, and the same number of inci- 
sors are at a more advanced stage of growth within the 
jaws, in addition to the canme teeth, which make 
their appearance about this time. 

" No wonder then that the eruption of so many teeth 
is a source of irritation and fever. The best treatment 
is to throw the animal off work, turn him to grass if 
the weather permits, or into a loose box in a well ven- 
tilated spot, and give him rest until the process of den- 
tition is completed. If the gums are red and swollen, 
lancing them will prove a source of great relief." 

On page 503 Prof. Williams, in speaking of crib- 
biting and wind-sucking, says: "Want of work and 
the irritation of teething are generally the causes of 
these vices." 



CHAPTER V. 

THE REMiTANT TEETH. 

Usually regarded as Plienomenons. — The Name. — Traced to 
tlie Fossil Horses, in which (in the Pliocene Period) they 
" Ceased to be Functionally Developed." — Nature's^ Meta- 
morphoses. — " The Agencies which are at work in Modeling 
Animal and Vegetable Forms." — Why Remnant Teeth are 
often, as it were, Prematurely Lost. — Fossil Horses and a 
Fossil Toothed-Bird. 

The Eemnant or " so-called wolf-teeth " are one of 
the most interesting features of the horse's dental sys- 
tem. They are generally regarded as phenomenons, 
but their line of descent is as direct as that of the first 
premolars (grinders), which have, as it were, almost 
absorbed them, and have increased in bulk nearly in 
proportion to the decrease in bulk of the Remnant 
teeth. 

As the word "wolf" is another name for that which 
is hurtful or destructive, and as these teeth as well as 
supernumerary teeth, with which, however, they should 
never be confounded, sometimes do injury, the generic 
name, " wolf-teeth," is not a bad one. But, since these 
particular teeth are hereditary, being beyond doubt the 
remains of teeth that were once functionally developed, 
they require a specific name ; I have therefore adopted 
the name Remj^ant Teeth. 



PROF, marsh's researches. 95 

In the evolution of the horse from an animfil of 
about the size of a fox to his present proportions, it is 
not strange that radical physical changes, of the teeth 
as well as other organs, should have occurred, or that 
they are in harmony with his bodily requirements as 
well as his usefulness to man. Small, four-toed limbs 
would support the body of an animal no larger than a 
fox or a sheep, but they would require additional size 
and strength to support tlie small horse (Hipparion) 
of the Pliocene period, or the large horse of the present 
period (E(jaus). This additional strength was gradu- 
ally acquired by the enlargement of the limbs and the 
solidification, as it were, of four toes into one, it being 
as natural, in conformity to the law of adaptation, for 
a line of succeeding animal forms to undergo bodily 
clianges as for an individual form to do so. 

During these metamorphoses equally varied and 
interesting changes occurred in the horse's dental sys- 
tem, which are described by Prof. 0. C. Marsh, of Yale 
College, in the article " Horse, Fossil," in " Johnson's 
New Universal Cyclopedia (vol. ii, p. 996). He gives a 
general description of the changes that have occurred 
in species of three geological periods, namely, the 
Pliocene, Miocene, and Eocen^e, those of the two last 
named having forty-four functionally developed teeth. 
The part of the article which refers to the teeth is as 
follows : 

"In the Pliocene tertiary period the horse was rep- 
resented by several extinct genera, the best known be- 
ing Hipparion (or Hippotberium). The species are 
small, as the name implies, Hipparion being a dimin- 
utive from tlie Greek Jiippos, a ' horse.' In the upper 
molar teeth there is in Hipparion, on the anterior por- 



96 THE REM^nA^T teeth. 

tion of the inner side, an isolated ellipse of enamel 
inclosing dentine, and not joined with the main body 
of the tooth by an isthmus of dentine, as in Equus, at 
least until the teeth are nearly worn out. Anchippus, 
also from the Pliocene, resembled in its teeth Anchi- 
therium of the Miocene, a genus now considered as 
typical of a family distinct from that of the horse. In 
Anchitherium the molars have short crowns, deyoid of 
cement, and are inserted by distinct roots. The Mio- 
cene species were not larger than a sheep. The Eocene 
representatives of the group were still smaller, the 
largest hardly exceeding a fox in size. They belong 
to the genus Orohippus. The dentition is very simi- 
lar to that of Anchitherium, but the first upper pre- 
molar is larger and the succeeding ones smaller than 
in that genus. The diastema, or * place for the bit,' is 
distinct. The canines are large, and near the incisors. 
The crowns of the molars are short and destitute of 
cement, and the skeleton is decidedly equine in its 
general features. 

"The gradual elongation of the head and neck may 
be said to have already begun in Orohippus, if we 
compare that form with other most nearly allied mam- 
mals. The diastema was well developed even then, but 
increased materially in succeeding genera. The num- 
ber of teeth remained the same until the Pliocene, 
when the front loiver premolar 2uas lost, and subse- 
quently the corresponding vpper tooth ceased to he func- 
tionally developed.'^ The next upper premolar, which 
in Orohippus was the smallest of the six posterior 



* The italics are mine. This " corresponding upper tooth 
that ceased to be functionally developed," is the identical tooth 
that now appears a«! a mere remnant. 



THE LARGE TUSHES OF ORJUIPPUS. 97 

teeth, rapidl}' increased in size, and finally became the 
largest of liie series. The grinding teeth had at first 
very siiort crowns, without cement, and were inserted 
by distinct roots. In Pliocene species the molars be- 
came longer, and were more or less coated with cement. 
The modern horse has very long grinders, without 
true roots, wliich are covered with a thick external 
layer of cement. Tlie large canines of Orohippus be- 
came gradually reduced in the later genera, and the 
characteristic 'mark' upon the incisors is found only 
in the later forms. It is an interesting fact that the 
peculiarly equine features accpiired by Orohippus are 
retained persistently throughout the entire series of 
succeeding forms." * 

* "The ancient Orohippus had all four digits of the fore-feet 
well dev'elo;)eci. In Mesohippus, of th3 next period, the fifth 
toe is only represented by a rudimenr, and the limb is supported 
by the second, third, and fourth, the middle one being the 
largest. Hipparion of the Later Tertiary still has three digits, 
but the third is much stouter, and the outer toes have ceased to 
be of use, as they do not touch the ground. In Equus the lat- 
eral hoofs are gone, and the digits tliemselves are represented 
only by the rudimentary splint bones. The middle or third 
digit supports the limb, and its size has increased accordingly. 
Tlie corresponding changes in the posterior limb of these genera 
are very similar but not so striking, as the oldest type (Orohip- 
pus) had but three toes behind. The earlier ancestor of the 
^roup, perhaps in the lowest Eocene, probably had four on this 
foot and five in front. Such a predecessor is as clearly indicated 
by the feet of Orohippus as the latter is by its Miocene relative. 
A still older ancestor, possibly in the Cretaceous, doubtless had 
five toes on each foot, the typical number in mammals. This 
reduction in the number of toes may perhaps have been due to 
elevation of the region inhabited, which gradually led the ani- 
mils to live on higher ground, instead of the soft lowlands, 
where a many-t6ed foot would be most useful." — Prof. 0, C. 
Marsh. 

5 



98 THE LiEM:NA:>rT teeth. 

The article closes as follows: 

"Such is, in brief, a general outline of the more 
marked changes that appear to have produced in 
America the highly specialized modern Equus from 
its diminutive, four-toed predecessor, the Eocene Oro- 
hippus. The line of descent appears to have been 
direct, and the remains now known supply every im- 
portant intermediate form. Considering the remark- 
able development of the group throughout the entire 
tertiary period, and its existence even later, it seems 
very strange that none of tlie species should have sur- 
vived, and that w^e are indebted for our present horse 
to the Old World."* 

* The followiiifr extracts from Prof. C. S. Tomes's "Dental 
Anatomy, Human and Comparative" (pp. 247-8, 254-5), explain 
some of tiie causes of tlie metamorphosris described by Prof. 
Marsli ; " He would indeed be a rasli man who ventured to as- 
sert that wo had recognized all the agencies wliich are at work 
in the modaling of animal and vegetable forms ; but it is safe to 
say that, at the present time, we are acquainted with several 
agencies which are in constant operation, and which are com- 
petent to profoundly modify animals in successive generations. 
We know of 'natural selection,' or ' survival of the fittest,' an 
agency by which variations beneficial to their possessors will be 
preserved and intensified in successive generations ; of ' sexual 
selection,' vt'hich operates principally by enabling those pos- 
sessed of certain characters to propagate their race, while others 
less favored do not get the opportunity of so doing ; of ' con- 
comitant variation' between diflferent parts of the body, an 
agency much more recondite in its operations, but by which 
agencies affecting one part may secondarily bring about altera- 
tions in some other part. 

"The doctrine of natural selection, or survival of the fittest, 
is as applicable to the teeth of an animal as to any part of its 
organization, and the operation of this natural law will be con- 
stantly tending to produce advantages or 'adaptive' differences. 
On the other hand, th.e strong power of inheritance is tending to 



NOT TARE, BL'T EASILY LOST. 99 

Remnant teeth are not rare, but it is rare for them 
to persist in the jaws till even middle age. However, 

preserve even that which, in the altering conditions of life, has 
become of very little us3. Thus we may understand riidimeutary 
testh to be teetli which are in process of disappearance, having 
ceased to be useful to their possessors, but still for a time, 
through the influence of inheritanc.\ lingering upon the scene. 
Some teeth have disappeared utterly. Thus the upper incisors 
of ruminants are gone, and no rudiments exist at any stage ; 
others siill remain in a stunted form, and do not persist through- 
out the lifetime of the animal, ns, f )r instance, the first premo- 
lars of t!in horse, or two out of the four premolars of most bears. 

"Teeth are profoundly susceptible of modification, but amid 
all their varied forms, the evidences of descent from ancestors 
whose teeth departed less from the typical mammalian dentition 
are clearly traceable by tlie existence of rudimentary teeth and 
other such characters. * * ■'' The power of inheritance is 
constantly asserting itself by the retention, for a time at least, 
of parts which have become useless, and by the occasional reap- 
pearance of characters which have been lost. * * * Things 
that are rudimentary often teach us most ; for being of no pres- 
ent use, they are not undergoing that rapid change in adaptation 
to the animal's habits which may be going on in organs that 
are actively employed." 

Horses are not the only animals that have had or are having 
changes in their dentition. Mr. C. R. Darwin says (" Descent of 
Man," vol. i, p. 25): "It appears as if the posterior molar or 
wisdom-teeth were tending to become rudimentary in the more 
civilized races of men. They are rather smaller than the other 
teeth. In the Melanian races, on the other hand, the wisdom- 
teeth are usually furnished with three se[)arate fanp^s, are gen- 
erally sound, and differ in size from the other molars less than 
in the Caucasian races. Prof. Sch.aaff haug.^n accounts for this 
difference «bpt ween the races by 'the posterior dental portion of 
th^ jaw being always shortened ' in those that are civilized, and 
this shortening may, I presume, be safelv attributed to civilized 
men habitually feeding on soft, cooked food, and thus using 
their jaws l?ss. I am informed by Mr. Brace that it is becoming 
quite a common pracrice in the United States to remove some 




100 TB"E EZMXAXT TEETH. 

there may be cases wliere they never appear; but' it 
by no means follows that because a horse is not in pos- 
session of them that he never had any. There are 
various causes for their frequent absence, but the chief 
cause is their small size. Remnant 
teeth of the lower jaw, which are 
very rare, are probably cases of " re- 
version to a former state." * If these 
latter teeth were not expelled in the j,^.,, ,,,, ,^^,^ ^ ^,,,^,„.^^ 
manner explained below by Mons. ^i-^- original. 

Lecoq, the probability is that they would not long 
withstand the friction of the bit. The upper teeth, 
however, while they may sometimes be expelled by the 
bit, are comparatively little disturbed by it, which 
probably accounts for their now and then remaining 
in the jaws for years. Anotlier reason for their per- 
sistence is that their roots are long in proportion to 
their bodies. The reason why these teeth should not 
be confounded with supernumerary or abnormal teeth 
will appear in the succeeding chapter, which is devoted 
to the consideration of the latter. 

Monsieur Lecoq gives cogent reasons for the fre- 
quent absence of Remnant teeth. He says: 

" Supplementary molars are sometimes met with in 
front of the true ones, and there may be four of them, 
two in either jaw, above and below. They are small 
teeth, having but little recemblance to the others, are 
frequently shed with the first deciduous molar, and 
are not replaced. The first replacing (permanent) 
molar is always a little more elongated than that 

of the molar teeth of children, as the jaw does not grow large 
enoiio-h for the perfect development of the normal number." 
* See the second reference note, page 80. 



HOW TTIEY MAY BE LOST. lOl 

which it succeeds, and it frequently expels at the same 
time the supplementary molar; so that if forty-four 
teeth be developed in the male horse, it is very rare 
that they are all present at the same time." 

That Remnant teeth are usually regarded as phe- 
nomenons is abundantly proved by some of the ex- 
tracts that follow. In ''Johnson's Xew Universal 
Cyclopedia" (p. 905), article ''Horse," it is said: 

"An additional small tooth is occasionally found in 
advance of the upper molar series. This tooth, when 
present, is the smallest of all the teeth, and, as it has 
neitlier predecessor nor successor, its nature is in 
doubt." 

As the nature of these teeth appeared to be clearly 
explained in the article " Horse, Fossil," which imme- 
diately follows that on the " Horse," I wrote to Prof. 
Joseph Leidy, telling him I believed the "wolf-teeth" 
were the remnants of the teeth that "ceased to be 
functionally developed," and asked his opinion about 
the matter. Writing under date of "Philadelphia, 
Nov. 26, 1878," he said: 

* * * "I tliink you are right in supposing that 
the little premolars referred to by Prof. Marsh as the 
' corresponding upper teeth,' which 'ceased to be func- 
tionally developed,' are the so-called 'wolf-teeth.'" 

Another letter, addressed to Prof. Theodore Gill, 
elicited the following repW, which was dated "Smith- 
sonian Institution, AVashington, D. C, IS'ov. 25, 1878:" 

* * '•• "The complete dentition of the adult 
horse is represented by the formnla : I., |; C j ; 
D., i; P. M., -I; M., J x 2 = 42. The 'small wolf or 



102 THE REMNANT TEETH. 

superanmerary tooth that appears in front of the first 
upper premolar,' is the more or less persistent first 
deciduous molar (d 1) of the first series, which is not 
succeeded by a first premolar. The premolars are con- 
sequently P. M., 2, 3, and 4 of the typical educabilian 
dentition.'^ 

Prof. Eichard Owen, who, like Drs. Gill and Leidy, 
has a clear conception of the subject, says : 

" The second incisor appears between the twentieth 
and fortieth days, and about this time the first small, 
deciduous premolar takes its place. * * * The 
representative of the first premolar is a very small and 
simple rudiment, and is soon shed." 

Surgeon Charles Parnell, in a letter to the editor of 
"The Veterinarian" (1867, p. 287), says: 

"In reading Prof. George Varnell's articles on some 
of the diseases affecting the facial region of the horse's 
head, I notice a description of wolf-teeth. He says: 
*They have been supposed to be the cause of disease in 
the eyes of horses. This idea, however, is quite erro- 
neous; therefore I shall not occupy any space in dis- 
cussing this traditional error.' Well, I can safely say 
that I have in my time extracted a great many of these 
teeth, and not merely because they existed, hut because 
there was a weeping from both eyes, the cause of which 
was attributed to wolf-teeth, and generally in the 
course of a few weeks the weeping has ceased. But 
what convinces me that they do affect the eye is that 
in several cases where there were weeping and weak- 
ness of one eye only, I have found a wolf-tooth on the 
affected side only, and the recovery of the eye has in- 
variably followed the extraction of the tooth. The 



HORSES WITHOUT EARS. 103 

mucous membranes and lachrymal glands appear to 
be the parts affected, undoubtedly from some connec- 
tion through the nerves. If these teetli are allowed to 
remain in the horse's mouthy the sight will become 
more or less impaired." 

Might not this plan (extracting the teeth), if adopted 
by all surgeons, eventually rid horses of the so-called 
wolf-teeth? Nature may be aided or injured. The 
effect of interfering with nature is illustrated by the 
following extract from Prof. W. Youatt's work, ''The 
Horse" (p. 154): 

" The custom of cropping the ears of the horse orig- 
inated, to its shame, in Great Britain, and for many 
years was a practice not only cruel to the animal, but 
deprived it of much of its beauty. It was so obsti- 
nately persisted in that at length the deformity be- "^ 
came in some hereditary, and a breed of horses born 
without ears was produced." 

Extracting the Remnant teeth appears to aid rather 
than injure nature. The practice is therefore as com- 
mendable as the cropping of the ears is reprehensible, 
and if the same result should follow that Prof. Youatt 
says followed the cropping of the ears, it ought to be 
adopted. 

C. D. House, an American veterinary dentist, like 
Surgeon Parnell, invariably extracts the Remnant 
teeth. He not only claims that they sometimes injure 
the eyes, but that in some cases, when they encroach 
on the maxillary branch of the fifth pair of nerves, 
they cause the horse to act as if insane. He says he 
has more than once extracted these teeth when the 
"insane" horse was in an open field. When the tooth 



104 THE REMXAI^T TEETH. 

is drawn and the animal is relieved, it looks around 
and stares and acts as if wondering where it is and how 
it got there. Not more than one horse in twenty pos- 
sessing these teeth, he says, ever suffers injury to its 
eyes. 

Surgeon E. Jennings of Detroit has examined many 
fetuses and always found Remnant teeth germs ; dur- 
ing 37 years' practice, in more than 100 deaths under 
two years, not a single instance occurred where these 
teeth, or the germs which produce them, were not 
found. They will be found usually at the age of two 
years. 

Veterinary Dentist J. Ramsey of Boston treated a 
7-year-old horse in 1881 that had been " out of con- 
dition " for several years, and consequently had had 
several owners. He discovered a long Remnant tooth 
with such a vicious inclination toward the roof of the 
mouth as to interfere with the use of the tongue. As 
soon as the tooth was extracted the horse began to cat. 

Prof. Williams says of Remnant teeth ("Principles 
and Practice of Veterinary Surgery," p. 479): 

" Small supernumerary teeth are often met with in 
front of the grinders, called Mvolf-teeth.' They have 
been supposed to be a cause of ophthalmia, but this is 
doubtful. They can produce no inconvenience; but 
if requested to extract them a practitioner can hardly 
refuse. The best method is to remove them with the 
tooth-forceps. 

"The question as to the influence of the teeth on 
the eyes miglit perhaps be deemed worthy of discus- 
sion, inasmuch as the dental nerve is a branch of that 
which supplies the eyes with common sensibihty, 
namely, the fifth. The older writers maintain od that 



MOOX-BLIXDXLSS. 105 

' moon-blindness' was due to wolf-teeih, and the first 
procedure in the treatment was their removal. Now- 
adays, however, the supposition is not carried quite so 
far, and the utmost that can be said is that the irrita- 
tion of teething may be an exciting cause of ophthal- 
mia in animals whose constitutions are hereditarily or 
otherwise predisposed to the disease, and the removal 
of supernumerary teeth, or lancing the gums, may pos- 
sibly be followed by some remission of the ophthalmic 
symptoms." 

Prof. Youatt thus accounts for Kemnant teeth: 

*' In a few instances the permanent teeth do not rise 
immediately under the temporary, but somewhat by 
their side. Then, instead of the gradual process of ab- 
sorption, the root, being compressed sideways, dimin- 
ishes throughout its whole bulk. The crown dimin- 
ishes also, and the tooth is pushed out of its place to 
the forepart of the first grinder, and remains for a con- 
siderable time under the name of a wolf -tooth, causing 
swelling and soreness of the gums, and frequently 
woundi'Jig the cheeks. They would be gradually quite 
absorbed, but the process might be slow and the an- 
noyance great; therefore they are extracted." 

Prof Youatt's theory is unique, but it fails to give 
a satisfactory explanation oi: the "so-called wolfteeth.^' 
That a tooth should be pushed out of its place is sim- 
ple enough; but why would the first upper temporary 
grinder remain in the gum and take root and the first 
lower not ? That " they would be gradually quite ab- 
sorbed," is disproved by the fact that they sometimes 
persist till .old age; and this fact also disproves the 
assertion that "they are extracted." Some surgeons 



lOG FOS.ilL HOII.dES' teeth. 

do not extract them. Prof. Yonatt doubtless meant 
to say they should be extracted. 

As Remnant teeth are found functionally devel- 
oped in the jaws of fossil horses — ^in which they were 
the largest of all the teeth — a few extracts from the 
works of well-known men concerning fossil horses and 
their teeth will be appropriate as a conclusion to this 
chapter. Prof. Richard Owen says ("Odontography," 
vol. i, p. 575): 

" Cuvier was unable, from the materials at his com- 
mand, to detect any characters in the bones or teeth 
of the different existing species of Equus, or in the 
fossil remains of the same genus, by which he could 
distinguish them, save by their difference of size. 
Among the numerous teeth of a species of Equus as 
large as a horse fourteen and a half hands high, col- 
lected from the Oreston cavernous fissures, 1 have 
found specimens clearly indicating two distinct spe- 
cies, so far as specific differences may be founded on 
well-marked modifications of the teeth. 

"One of these, like the ordinary Equus fossilis of 
the drift and pleistocene formations, differs from the 
exhtmg Equus cabcdlus by the minor transverse diam- 
eter of the molar teeth ; the other, in the more com- 
plex and elegant plication of the enamel,* and in the 

* In Prof. Owen's "History of "British Fos^l Mammals and 
Birds" (pp. 393-4), the "elegant plication of the enamel" on 
the crown of this tooth is illustrated. Prof. Owen says ; " Fig. 
153 illustrates the character, above adverted to, of the complex 
plication of the enamel, as it appears on the g-rinding- surface of 
a partially worn upper molar tooth, the second of the right side. 
The leno^th of this tooth is three inches four lines, and the fangs 
had not begun to be formed. One cannot view the elegant fold- 
ings of the enamel iu the present fossil teeth, and in those of 



TEETH UXE.v:.T:iEr> AT ORLSTOX, EXG. 107 

bilobed posterior termin:ition of tlie grinding surfdce 
of tlie last upper molar, more closifly approximates to 
the extinct horso of the Miocene period, which Herr 
von Meyer has characterized under tlie name of Equus 
caballus jyrimigenius. The Orestou fos3il teeth differ, 
however, from this in the form of the tifth or internal 
prism of dentine in the upper molars, and in its con- 
tinuation with the auterior lobe of the teeth, the fifth 
prism being oval and insulated in the Equus ^jrimi- 
geniiis of Von Meyer. 

'- Tlie Oreston fossil teeth, which in their principal 
characters manifest so close a relationship with the 
Miocene Equus primigeiiius^ d'l^er, like the later drift 
species {Eq. fossilis), from the recent liorse in a greater 
proportional antero-posterior diameter of the crown, 
and also in a k-ss produced anterior angle of the first 
premolar. I have named this British fossil horse 
Equus pUcidens. The fossil horse (Eq. curvidens) of 
South America, which coexisted with the megathe- 
rium,! and, like it, became extinct apparently before 

the more ancient primigenial spocies (Hippotlieria) of the conti- 
nental Miocene deposits, without being reminded of the peculiar 
character of the enamel of the molars of the Elasmotheriura, in 
which it is folded in elegant festoons. This extinct pachyderm, 
which surpassed the rhinoceros in size, resembled that genus 
very closely in the general disposition of the folds of enamel in 
the grindinjr teatli, but agreed with the modern horse in the 
deep implantation of those teeth by an undivided base. The 
Elasmothere appears, therefore, to have formed one of the links, 
now lost, which connected the horse with the rhinoceros ; and 
it is interesting to observe that some of the extinct species of 
horse, in the analogous complexity of tlie enamel folds, more 
closely resembled the Elasmothere than do the present species." 
\ " The teeta of this most jrigantic of the extinct quadrupeds 
of the slotli tribe are small in proportion to the size of the ani- 



108 FOoSlL nOKSES' TEETH. 

the introduction of the human race, differs from the 
existing' horse by the greater degree of curvature of 
the upper molars." 

The following account of two fossil molar teeth of an 
extinct species of horse, discovered in South America, 
may be found in Prof. Owen's " Fossil Mammalia and 
Mammaha/' (pp. 108-9) : 

^'Notice of the remains of a species of Equus, found 
associated tcitli the extinct Edentals and Toxodon at 
Punta Alta, in Bahia Blanca, and luith the Mastodon 
and Toxodon at Santa Fe^ in Entre Rios. — The first of 
these remains is a superior molar tooth of the right 
side. It was imbedded in the quartz shingle, formed 
of pebbles strongly cemented together with calcareous 
matter, which adhered as closely to it as the corre- 
sponding matrix did to the associated fossil remains. 
The tooth was as completely fossilized as the remains 
of the mylodon, megatherium, and scelidothere, and 
was so far decomposed that in the attempt to detach 
the adherent matrix it became partially resolved into 
its component curved lamelh-e. Every point of com- 
parison that could be established proved it to differ 
from the tooth of the common Equus cahallus only in 
a slight inferiority of size. 

"The second evidence of the coexistence of the 
horse with the extinct mammals of the tertiary epoch 
of South America reposes on a more perfect tooth, 
likewise of the upper jaw, from the red argillaceous 

mal. They are five in number on each side of the upper jaw, 
and, probably, four on each side of the lower. They present a 
more or less tetragonal figure, and liave the grinding surface 
traversed by two transverse angular ridges." — Owen. 



IX SOUTH A.MEKICA. 109 

earth of the Pampas afc Bojada de Santa Fe, in the 
Province of Entre Eios. This tooth a^eed so closely 
in color and condition with the remains of the masto- 
don and toxodon, from the same locality, that I have 
no doubt respecting the contemporaneous existence of 
the individual horse of which it once formed part. 
This tooth is figured at Plate xxxii, Figs. 13 and 14, 
from which the anatomist can judge of its close corre- 
spondence with a middle molar of the left side of the 
upper jaw. 

''This evidence^ of the former existence of a genus 
which, as regards South America, had become extinct, 
and has a second time been introduced into that conti, 
nent, is not one of the least interesting points of Mr. 
Darwin's paleontological discoveries.'' * 



* Mr. Darwin, in his work on " Tlie Descent of Man" (vol. i, 
pp. 2G0-1), says : " Altbougli the gradual decrease and final ex- 
tinction of the races of man is an obscure problem, we can see 
that it depends on many causes, differing in different places and 
at different times. It is the same difficult problem as that pre- 
sented by the extinction of one of the higher animals— of the 
fossil horse, for instance— which disappeared from South Amer- 
ica, soon to be replaced, within the same districts, by countless 
herds of the Spanish horse." 

In his "Journal of Researches" (pp. 130-1-2), Mr. Darwin 
gives further information concerning the fossil teeth described 
by Prof Owen, and advances a theory of the introduction of the 
horse into the " so-called New World." He says : " In the Pam- 
paean deposit of the Bojada I found the osseous annor of a gigan- 
tic, armadillo-like animal, the inside of which, when the earth 
was removed, was like a crreat cauldron. I also found teeth of 
the toxodon and mastodon, and one of a horse, in the same 
stained and decayed state. The latter greatly interested me, and 
I took scrupulous care in ascertaining that it had been im- 
bedded conteni^ioraneously with the other remains ; for I was 
not then aware that among the fossils from Bahia Blanca there 



110 FOSSIL HORSES' TEETH. 

Prof. Thomas H. Huxley says (" Critiques and Ad- 
dresses," pp. 191-5) : 

" Let us endeavor to find some cases of true linear 
types, or forms which are intermediate between others, 
because they stand in a direct genetic relation to them. 
It is no easy matter to find clear and unmistakable 
eyidence of filiation among fossil animals. After much 

was a horse's tooth hidden in the matrix ; nor was it then known 
with certainty that the remains of horses were cammon in North 
America. Mr. Lyell has lately brought frftm the United States 
a tooth of a horse ; and it is an interesting fact that Prof. Owen 
could find in no species, either fossil or recent, a slight but pecu- 
liar curvature characterizing it, until he thought of comparing 
it with my specimen found here. Certainly it is a marvelous 
fact in the history of the Mammalia, that in South America a 
native horse should have lived and disappeared, to be succeeded 
in after ages by tlie countless herds descended from the few in- 
troduced by the Spanish colonists ! (I need hardly state here 
that there is good evidence against any horse living in America 
at the time of Columbus). 

" When America, and especially North America, possessed its 
elephants, mastodons, horse, and hollow-horned ruminants, it 
was much more closely related in its zoological characters to the 
temperate parts of Europe and Asia than it now is. As the 
remains of these genera are found on both sides of Behring's 
Straits and on the plains of Siberia, we are led to look to the 
northwestern side of North America as the former point of com- 
munication between the Old and the so called New World. And 
as so many species, both living and extinct, of these same genera 
inhabit and have inhabited the Old World, it seems most prob- 
able that the North American elephants, mastodons, horse, and 
hollow-horned ruminants migrated — on land since submerged 
near Behring's Straits— from Siberia into North America, and 
thence — on land since submerged in the West Indies— into 
South America, where for a time they mingled with the forms 
characteristic of that southern continent, and have since become 
extinct." 



HIPPARIOX AND A>;cniTIIERIU-\r. Ill 

search, however, I tliink that such a case is to ho made 
out in favor of the "horses. The moderu horse is rep- 
resented as f\ir back as the latter part of the Miocene 
epoch; but in deposits belonging to the middle of that 
epoch its pkice is taken by two other genera, Hipparion 
and Anchitherium. A species of Anchithcrium was 
referred by Cuvier to the Paleotheria. The grinding 
teeth are in fact very similar in shape and in pattern, 
and in the absence of any thick layc'r of cement, to 
those of some species of Paleotherium. But in the 
fact that tlrere are only six full-sized grinders in the 
lower jaw, the first premolar being very small; that the 
anterior grinders are as large as or rather larger than 
the posterior ones; that the second premolar has an 
anterior prolongation, and that the posterior molar of 
the lower jaw has, as Cuvier pointed out, a posterior 
lobe of much smaller size and different form, the den- 
tition of Anchithcrium departs from the type of the 
Paleotherium and approaches that of the horse. The 
skeleton of Anchitherium is extremely equine. 

'' In the Hipparion the teeth nearly resemble those 
of the horse, though the crowns of the grinders are not 
so long. Like those of the horse, they are abundantly 
coated with cement. In the modern horse, finally, the 
crowns of tlie grinding teeth become longer, and their 
patterns are slightly modified." 

Alfred Rnssel Wallace, RRG.S., &c., says ('-The 
Geographical Distribution of Animals," New York 
edition, vol. i, p. 135): 

^'Ungvlata.—'VhQ animals belonging to this order 
being usually of large size and accustomed to feed and 
travel in herds, are liable to wholesale destruction by 
floods, bogs, precipices, drought, or hunger. It is for 



112 rOSbIL HOUSES. 

thes3 reaions, probably, that tlieir remains are almost 
always more numerous than those of other orders of 
mammalia. In America they are especially abundant. 
^'The true horses are represented in the Pliocene by 
several ancestral forms. The most nearly allied to the 
modern horse is Pliohippus, consisting of animals 
about the size of an ass, with lateral toes not exter- 
nally developed, but with some differences of dentition. 
Next come Protohippus and Hipparion, in which the 
lateral toes are developed, but are small and function- 
less, Protohippus being only two feet and a half high. 
Then we have the allied genera, Anchippus, Merychip- 
pus, and Hyobippus, which were still smaller animals. 
In the older deposits we come to a series of forms, still 
unmistakably equine, but with three or more toes used 
for locomotion, and with numerous differentiations in 
form, proportions, and dentition. In the Miocene we 
have the genera Anchitherium, Miohippus, and Meso- 
hippus, with three toes on each foot, and about the 
size of a sheep or large goat. In the Eocene of Utah 
and Wyoming w^e get a step further back, several spe- 
cies having been discovered about the size of a fox, 
with four toes in front and three behind. These form 
the genus Orohippus, and are the oldest ancestral 
horse known." 

The following account of a horse's tooth that was 
found while digging a well is from The Popular Science 
Eeview : 

"In a paper read before the St. Louis Academy of 
Science, and reported in The American Naturalist for 
March, 1871, Mr. G. C. Broadhead records some in- 
teresting facts about fossil horses. Alluding to the 
fact that horse remains have been found in the altered 



A TOOTH FOUXD IN DIGGING A WELL. 113 

drift of Kansas, lie says he is now able to announce 
that similar remain^ have been discovered in a well afc 
Papinville, Bates County, Mo. Mr. O. P. Ohlinger, 
while digging a well, uneartlied a tooth at a depth of 
thirty-oae feet from the surface ; it was resting in a 
bed of sand beneath a 4-inch stratum of bluish clay 
and gravel. Beneath the sand containing tlie tooth 
was a gravel-bed five feet in thickness. He sent the 
tooth to Prof. Joseph Leidy, of Philadelphia, who pro- 
nounced it to be the last upper molai- of a horse, prob- 
ably an extinct species." 

In various volumes of the " Proceedings of the Acad- 
emy of Natural Sciences of Philadelpiiia," accounts of 
many other fossil horses' teeth may be found, of which 
the following is a specimen (" Proceedings," &c., 1871, 
p. 113): 

"Prof. Joseph Leidy exhibited a specimen of an 
upper molar tooth, which Mr. Timothy Conrad had 
picked up from a pile of Miocene marl at Greenville, 
Pitt County, N. C. He believed, from its size and the 
intricacy in the folding of the enamel of the islets at 
the middle of the triturating surface, that the tooth 
belonged to the Post- Pliocene Equus complicatus, and 
was an accidental occupant of the Miocene marl. It 
might, however, belong to a Hipparion of the Miocene 
period, but the imperfection of the specimen at its in- 
ner part prevented its j>ositive generic determination." 

The discoveries of horse remains since 1880 by Prof. 
E. D. Cope, one of the editors of Tlie American 
NatiiraHsf,MVQ. of an extraordinary character, and an 
interesting account of them appears in the Appendix 
to this work. Truly the Americas are rich in fossil 



114 BIRDS WITH TRUE TEETH. 

remains, and it is becoming a common thing to hear 
of the unearthing of mastodons, elephants, etc. 

Note. — The birds of the present epoch are entirely desti- 
tute of true teeth, and the mandibles have generally more or 
less trenchant, unarmed linear edges ; but sometimes they are 
armed with processes of bone simulating teeth, but in no other 
respect entitled to that name. In former epochs, however, 
there existed types actually ])rovided with true teeth, having 
all the structural characteristics of those organs, and fitting in 
sockets in the jaws. These have been combined by Marsh 
mider the general term Odontornitlies (toothed hirds). — Gill. 

The teeth of Hesperornis were covered with smooth enamel, 
terminating upward in conical pointed crowns and downward 
in stout roots. The young tooth probably formed on the inner 
side of the root of the tooth in use, a pit for its reception being 
gradually made by absorption. The old tooth, being progres- 
sively undermined, was finally expelled by its successor, the 
number of teeth thus remaining unchanged. The teeth were 
implanted in a common alveolar groove, as in Ichthyosaurus. 
The skeleton measures about 6 feet from the point of the tail to 
the end of the bill. Hesperornis regalin appears to have had 14 
functional teeth in the upper and 33 in the lower jaw, — Marsh. 

A fossil is the body or any known part or trace of an animal 
or plant buried by natural causes in the earth. The molds of 
shells, the impressions left by the feet of animals in wal]>:ing, 
implements of stone or metal, and other works of human art 
which have been accumulated naturally into rubbish-heaps, 
are thus strictly fossils. Perhaps the marks of rain, wind, 
waves, and shrinkage through heat should be included. * * * 
Fossils indicate the former existence of organic races now 
entirely extinct ; that, as a whole, each successive period con- 
tained more highly organized structures than its predecessor; 
that tropical forms once flourished in the polar regions ; that 
each epoch was characterized by peculiar groups. Hence, for- 
mations are identified in new countries by means of fossils. — 
a H. mtchcoct. 

For interesting articles on Fossil Botany, Fossil Fishes, 
Fossil Footprints, and Fossil Forests, the reader is referred to 
Johnson's "New Universal Cyclopedia," vol, ii, pp. 231-0. 



CHAPTER VI. 

DENTAL CYSTS AND SUPERXUMERARY TEETH. 

Teeth trrowing in various parts of the Body. — Some Cysts more 
Prolific than others, Producing a Second, it" not a Third, 
"Dentition." — Reports and Theories oi Scientific Men. — 
Cases of Third Dentition in Human Beings. 

The development of abnormal teeth in different 
parts of the body (the human body as well as those of 
the lower animals, particularly the horse), is not the 
least interesting feature in the stndy of dental science. 
To judge from the reports that follow, one would think 
the tooth-substance in some horses was an unknown 
quantity. It would be interesting and useful to know 
wiiatlier in such cases the natural teeth are in a per- 
fectly healthy state, and whether the temperature is 
natural, instead of being increased, as during certain 
periods of teething. While the study of these teeth 
may not be of paramount importance, it serves -to 
further illustrate the physiological relations of the den- 
tal system, and ought to assist the surgeon in more 
correctly diagnosing diseases. 

Surgeon George Fleming, of the Royal Engineers, 
contributed a valuable paper entitled "Dental Cysts, 
or Tooth-Bearing Tumors," to " The Veterinarian" for 
1874 (p. 692), the substance of which is as follows: 

" In The -Gazetta Medico- Veterinaria of Milan for 
1873 (p. 274), Profs. Lanzillotli-Buonsanti and Gui- 



116 DENTAL CYSTS. 

seppe General!, of the Veterinary School of that city, 
published a most complete and interesting contribu- 
tion to our knowledge of the pathology of dental cysts 
in the horse, well illusLrated with wood-cuts, and in- 
cluding a full bibliographical record and synoptical 
table of these morbid productions. From their re- 
searches it would appear that dental cysts were first 
described by Mage Grouille, in 1811.* 

" These teeth-bearing tumors have received different 
names. Thus they have been designated 'erratic' or 
* misplaced teeth,' 'dental neoplasies,' 'odontocysts,' 
"'dental degeneration of the temporal bone,' 'temporal 
fistula,' 'abnormal development of teeth in unusual 
places,' 'auricular teeth,' 'odontocele,' and 'dentiger- 
ous cysts' or 'teeth tumors.' They may be developed 
in unusual places, such as the temporal region, the 
frontal bones, the base of the ear, the space between 
the branches of the lower jaw, the lumbar region, the 
testicles, and the ovaries. Coleman stands alone in his 
case of a cyst found beneatli the right kidney, in which 
w^ere two small molars and an incisor, attached to a 
bone that resembled a jaw, though the Milan profes- 
sors believe th.e teeth in this instance may have been 
developed in a testicle retained in the abdominal cav- 
ity. The most common situation is undoubtedly in 
the temporal region, as in seventy-five recorded cases 
sixty-eight were observed there. These cases all refer 
to the horse. Berger-Perriere, however, found a tem- 
porary incisor in a fistulous wound near the right ear 

* "No mention is made of the Khhiyevoiievol h role yvd6oLc,OT 
maxillary exostoses of Apsyrtus (' Hipp. Gr.' p. 64), who recom- 
mends tliat these tumors sliould be carefully and completely 
removed, or they will return of a larger size." 

Tha reference note is also Surc^eon Fleming's. 



A CYST MISTAKEN FOIl GLANDERS. 117 

of a lamb two months and a half old {' Recucil de 
Med. Vetenuflire,' 1835, p. 586). 

'•In most instances only one tooth is fonnd. Gurlt 
was the first to find, on the mastoid process of the 
temporal bone, a mass of molar teeth fused, as it were, 
together. The tumor was three inches and a half 
high, and about two in its largest diameter. The liorse 
had been destroyed for glanders. Goubaux found two 
at the posterior portion of the sphenoid bone, and Bay 
four. In a cyst of the testicle Gurlt discovered six 
teetli, three separate and three in a mass. Bay at- 
tended a horse iii 1800 that appeared to be suffering 
witli encephalitis. It died twenty-four hours after his 
visit. It had always shown, on the right temporal re- 
gion, a tumor without a fistula, but it did not attract 
notice, as it apparently.caused no inconvenience. Nine 
years afterward, when Bay was preparing the head as 
a pathological specimen, he discovered this supposed 
exostosis to be constituted by the union of four molar 
teeth. The two superior teeth projected from the 
temporal articulation, and the inferior two were situ- 
ated in the petrous portion of the temporal bone, in- 
dining obliquely from within outward. The posterior 
portion of the latter projected in a very salient manner 
at the seUa lurcica, and must have produced much 
pressure on important parts of the brain. 

"Age does not appear to have any influence on the 
development of these cysts, the animals in which they 
have Ijeen observed ranging in age from eight or nine 
months to fifteen years. The period of formation also 
varied greatly. In regard to the side of the body in 
Avhich they were developed, in seventeen cases they 
were on the left, and in thirteen on the right. In 
f jurtoen cases obL^erved by Maerops, they were indiffer- 



118 DEXTAL CYSTS. 

ently on both sides. In tliis respect clinical observa- 
tion has not yielded any fact of practical* importance. 

" Sometimes, after the extraction of a tooth, it hap- 
jDens that the cavity of the cyst or the bottom of the 
fistula does not cicatrize. This is a sure indication 
that a new tooth is forming. Eodet noted this fact as 
long ago as 1827. Macrops has observed a case of this 
kind. He was compelled to operate twice within three 
months, each time removing a molar tooth; and wdien 
he made his report, in 1860, it was probable that a 
third tooth was being developed, as the fistula had not 
closed." 

Surgeon Fleming also mentions cases that were ob- 
served by Surgeons Perosino, Martin, Harold, Gamgee, 
Coclet, Lafosse, and others. He continues: 

"Profs. Lanzillotti-Buonsanti and G-enerali made 
minute inspection of a specimen of tooth taken from 
the base of the ear of a foal twenty months old, and 
they report that microscopically the structure of sucli 
teeth does not differ much from natural teeth. The 
same constituents — dentine, enamel, and cement — 
were found, the only ditlerence being that they were 
arranged in an unusual manner. In the tooth they 
examined, for instance, the cement was abundant in 
the central part, while in that studied by Oreste and 
Falconio, the dentine was most abundant and the 
cement least in quantity." 

Surgeon Fleming next refers to and gives a sum- 
mary of the views of scientific men, who say that "A 
certain number of teeth may sometimes be developed 
as parasitic productions in a cavity similar to and situ- 
ated near the mouth (in which category is included 



A FETUS WITIIi:>T A TETUS. 119 

the excellent case occurring iu a woman, and de- 
scribed, in 1802, by Prof. General! — an observation 
nnique in the teratology of mimkind — namely, a 
case of parasitic monstrosity, in whichy however, the 
designation 'dental cyst/ so inexact iu itself, is in- 
appropriate and fiilse);" tliat "the ovarian cysts in 
women, in which have been found pieces of bone and 
cartilage, teeth, and a lower jaw, more or less do- 
formed, ought to be considered as probable cases of 
ovarian impregnation with an incompletely developed 
fetus, and in young girls as examples of the intra- 
uterine formation of a fetus witlnn a fetus ;^' that 
"only in this way can be explained the lipomatous 
and sarcomatous congenital mas^s contained in cysts, 
with the teeth and fragments of bone simulating an 
incomplete jaw, which have been observed on the 
human orbit (Lobstein and Travers), on the palate 
(Otto), on the tongue (Stansky), on the side of the 
jaw, in the cheek, and on the neck, but which Schultze 
and Panum consider as the simple proliferation of em- 
bryonic plasmatic cl41s;" that '• some dental cysts are 
true dermoid cysts, containing hair and teeth," &c., 
and closes his paper with the following common-sense 
suggestion : 

" Perhaps direct researches, which have not yet been 
made, carried out in favorable circumstances, will bet- 
ter serve in deciding their real nature than all the 
more or less brilliant academical reasoning." 

John Gamgee, Professor of Anatomy and Physiology 
in the Edinburgh Veterinary College, in the course of 
a series of articles on various subjects in " The Veter- 
inarian" for 185G, thus comments on a case of dentig- 
erous cyst, the history of which was originally written 



1:20 DENTAL CYoTS. 

by Moiisienr Lafo3se and published in the '•Journal 
des Veterinairo da Midi : " 

*'M. Lafosso, Professor of Clinical Medicine in the 
Veterinary School of Toulouse, had nnder his treat- 
ment a four-year-old mare that fjr two months before 
admission into the infirmary wai aifected with a phleg- 
monous tumor in tlie region of the left ee.r. This was 
opened. The wound that resulted rapidly contracted, 
but a fistula remained. When Lafosse first saw the 
case, he found a painful tumor, with a granulating 
w^ound just behind the scutiforra cartilage, and near 
the upper i)art of the parotid gland. By probing he 
ascertained that at the bottom of the fistulous tract 
Av\:s some hard substance, which he supposed to be the 
scutiform cartilage in an ossiiied state, or a portion of 
the temporal bone exfoliating. A severe operation 
Avas performed, and the solid substance extracted. It 
was double, deeply seated, and firmly adherent to sur- 
rounding textures. Slight hemorrhage ensued from 
the division of the anterior auricular, but was easily 
stopped. The wound was dressed, and the animal 
soon recovered, having shown only a few symptoms of 
sore throat after the operalion. 

" I shall not translate M. Lafosso's description of 
the products he extracted. They were composed of 
tooth-substance, and althougii it has been questioned 
whether it is real tooth that is developed in the shape 
of accidental growths in the region of the ear, still the 
fact is now well established, however puzzling to the 
minds of some it may be to comprehend their origin. 

'- Lafosse attempts a teratological explanation, but 
asks : 'If teeth are looked on as arising from the tcgu- 
montary system, considermg them in most animals as 



TEETH EMAXATIXa TIIOM OSSEOUS SYSTEM. 121 

emanating from papillE© and mucous membrane, where 
was the dermoid papilla that constituted the basis of 
development of this tooth, deeply seated and close to 
the ear, especially as what might be taken as the 
crown looked toward the inner surface of the skin ?^ 

"Further on Lafosse shaws that in certain animals 
teeth absolutely emanate IVom the osseous system, as 
in the coluber scaher and other serpents, in which true 
osseous eminenc3s, cf)ated by enamel, pierce the esoph- 
agoan tunics, and project into the tube; they are at- 
tached to about thirty vertebrae, of which they form 
tlie inferior spinous process. These are intended to 
crush the eggs that tlie serpents feed upon. 

" Having established the fact that teeth may spring 
from bone as well as mucous membrane, Lafosse leads 
us, where we never suspected, to consider the dental 
tumors above spoken of as congenital, and he looks 
on them as having sprung from some rudiment of a 
maxillary bone. In a word, he looks on the abnormal 
tooth in question — without offering any plausible ex- 
planation—as an aberration in development. He does 
not class such teeth with the teeth formed in the 
ovary, &c., but rather with those instances where an 
extra limb or portion of an extremity is to be met with. 
It is an accidental excess of parts in an otherwise well- 
formed body. ^It cannot,' says Lafosse, 'be looked on 
as an osseous transformation of certain tissues.' 

"I have spoken of the case at length, for surgically 
it is of the very greatest interest. As pathological 
anatomists, it is our duty to study the laws of disease 
as well as health. It is praisew^orthy to dive into the 
mysteries of the origin of monsters, but it is essential 
to adhere to facts and not sacriiice them to theoretical 
explanations. 
6 



122 DEls^TAL CYSTS. 

" In common with others, I have studied several of 
these dental tumors. They may spring from several 
of the bones of the head, but especially from the region 
of the petrous temporal hone. They may project to- 
ward the interior of the cranium, but they more fre- 
quently project outwardly. They may be strongly 
implanted in the bone, or get separated; then they 
are maintained in their situation by the soft textures 
around. Their development is not more extraordinary 
than that of otlier osseous growths that spring from 
the cranial or maxillary bones; and their tooth-formed 
structure (teeth in the region of teeth), is not more 
wonderful than bony tumors in other parts of the sys- 
tem, whether connected or not with the skeleton.^' 

Prof William Sewell, President of the British Vet- 
erinary Medical Association, at the meeting of that 
body on May 15, 1838, advanced an interesting theory 
of the growth of abnormal teeth. It may be true, for 
after the teeth have attained their full growth, it is 
reasonable that the dental arteries are less active. But 
as the teeth continue to grow throughout life, a fact 
Prof. Sewell does not mention, it is not so reasonable 
that they even "in a manner cease^^ to act. The pro- 
fessor's remarks are thus reported ("Veterinarian," 
1838, "Proceedings Vet. Med. Ass.," p. 199): 

" The President begged leave to direct the attention 
of the meeting to a horse's tooth that had been pre- 
sented to him. It was a fine specimen of the anomaly 
occasionally observed m the dental system of the horse 
— the production of teeth in other places than the 
alveolar cavities, after the natural teeth had been per- 
fected. The situations which Xature in her wander- 
ings selected were occasionally very singular. He had 



TEETH LIKE A CALF'S YOUXG HORN. 123 

seen a tooth Avhicli grew from the petrous portion of 
the temi)oral bone, like a young liorn from the fore- 
head of a calf. It formed a hard and seemingly very 
painful tumor, which was ultimately opened, and the 
bony substance, which proved to be an almost perfect 
tooth, extracted. He had seen three or four :<imilar 
cases in which teeth had been thus produced. "When 
the dental arteries in a manner cease to act — the teeth 
having iitlained their full growth — there was a singu- 
lar predisposition in the neighboring arteries to take 
on the same action, and teeth, more or less perfect, 
were formed in parts altogether unconnected with den- 
tition. In this case there were two, one on either side 
of the forehead." 

Surgeon F. Denenbourg makes a detailed report in 
"The Veterinarian" for 18G9 (p. 533) of six cases of 
dental cyst, five of which he operated on successfully. 
The first case he treated was in 1837. He confesses 
that he believed them to be mucous tumors till 1851, 
w^hen he found a molar tooth perfectly formed. This 
tooth, which was deposited in an anatomical museum, 
was as large as a pigeon's egg, and had three roots. 

Sursreon C. C. Grice, of New York, makes the fol- 
lowing report ("Veterinarian," 1867, p. 39;^): 

"Whether the case the facts of which I am about to 
communicate will prove of sufficient interest to be pre- 
sented to the notice of the veterinary profession, or 
will add anytliing to the advancement of veterinary- 
pathology, I know not ; yet I would be glad to see it 
inserted in our respectaijle old journal, ' The Veteri- 
narian,' for I hold it to be the duty of every member 
of the profession to advance its interests to the best of 



124 DEi^TAL CYSTS. 

his ability. I send it because to me it is a very rare 
case. I have now been in i^ractice more than forty 
years, and I have not met with anything of the kind 
before. 

"At the request of Mr. Barn urn, a merchant of onr 
city and the owner of a breeding-farm in Westchester 
County, I attended a two-year-old colt, considered to 
be very valuable, as he comes from trotting stock. Mr. 
Barnum merely said the colt had a discharge from the 
base of the near ear, and that it had existed for ten 
months. 

"I found the animal so very shy on account, of the 
previous torturing of his attendants, that I could not 
approach him; therefore I had to cast him. The in- 
troduction of the probe failed to satisfy me that any 
foreign body existed there; but on dilating the orifice 
and introducing the most reliable of all probes, my 
forefinger, I discovered a hard substance, which was 
firmly attached to the temporal bone and surrounding 
parts. I could not grasp the substance with the for- 
ceps, therefore I used the handle of the instrument as 
a lever, and after using great force dislodged it. Mr. 
Barnum picked up something in the grass four or five 
yards from me, and it proved to be a molar tooth. On 
examining the wound afterward I found some loose 
fragments of bone, and on removing them they ap- 
peared to be the socket of the tooth. 

"1 would have sent you a report of this case earlier, 
but I was desirous of seeing its termination. Mr. Bar- 
num says the parts have entirely healed and left no 
blemish." 

Prof WilHam Williams advances an interesting the- 
ory regarding the cause of dental cysts and also the 



AMAUROSIS AXD ATROPHY OF THE EYES. I'^o 

manner of their formation. lie says (" Principles and 
Practice of Veterinary Surgery," p. 41^) : 

" Cysts containing teeth have been found in the tes- 
ticles and other parts of tlie body, but those which are 
of importance to practical men are found within the 
antrum. I have seen several cases of this kind, and 
have extracted teeth from cysts even so high as the 
base of the ear. 

"During life these tumors are distinguishable by- 
more or less disfigurement of the lace, by a bulging out 
of the superior maxillary bone, accompanied in some 
cases by amaurosis of one eye, succeeded by atrophy 
of the eye from the pressure of the growing tumor. 
In other cases these complications are not present, but 
now and then an abscess forms in the post-orbital re- 
gion, wiiich will be found on examination to contain a 
hard body — an imperfect tooth. 

" To understand the process by which these tumors 
are formed, it is necessary to remember that the teeth 
of all animals belong to and arise from the membran- 
ous portion of the digestive canal, and that at a very 
early period of fetal life a provision is made for the 
development of- the permanent teeth as well as the 
temporary. This provision, according to Goodsir, is 
as follows : ' As early as the sixth week of intra-uteral 
life (human), a groove appears along the border of the 
future jaws, called the primitire dental groove, which 
is lined by the membrane of the mouth. At the bot- 
tom of this groove projections— papillae— spring up, 
corresponding in numl)er with the temporary teeth. 
AVhile the growth of the papillae is going on, partitions 
are formed across the grooves, by which they become 
separated from each other. These partitions subse- 



126 DENTAL CYSTS. 

quently form the bony sockets, thus placing each 
papilla in a separate cavity. Concurrent with this 
process, small growths take place upon the membrane 
of the mouth, just as they dip into the papillary cavity 
or follicle, which finally, by union with otlier growths, 
form a lid which covers the papillae in a closed sac or 
bag. Before the final closing of the follicle, a slight 
folding ijiward of its lining membrane takes place. 
This inward folding of the membrane of the primitive 
groove is for the purpose of forming a new cavity — the 
cavity of reserve — which furnishes a delicate mucous 
membrane for the future formation of the permanent 
teeth. The cavity in which the permanent tooth is 
developed is a mere detachment from the lining of the 
primitive groove, and in it a papilla is formed in the 
same w^ay as that of a temporary tooth.^* 

" Now, I look on the formation of these tumors as 
being due to some irregularity in this folding of the 
lining membrane, by which tlie 'cavity of reserve' is 
made up of several folds ; that these folds eventually 
become separated, forming separate cavities of reserve, 
and that a papilla similar to those of the natural teeth 
is developed in each cavity. These irregular papillae 
are converted into irregular teeth, wiiich, for want of 
space in the mouth, are forced into the antrum, and 
may completely block it up, as w^ell as the posterior 
nasal opening. 

" I have classified them as cystic tumors, as at first 
they are inclosed in sacs or cysts. They soon burst 
through their investing membrane, however, and form 
a large tumor, composed entirely of teeth, having a 

* Compare Professor Goodsir's theory with those advanced 
by Messrs. Owen, Tomes, Chauveau, and others in the first 
chapter. 



A BULL WITH AX UPPER IXCISOK. 127 

great variety of shapes, and running in different direc- 
tions. The teeth vary in size, some being very small, 
while others are nearly as large as a permanent grinder. 
Each tooth has a pulp cavit}^, and is composed of the 
sam.^ substances as the natural teeth. Sliould their 
removal be desirable, it will be necessary to trephine 
the superior maxillary sinus and detach them with the 
forceps." 

In the chapter entitled "The Pathology of the 
Teeth" (the VIII.), Surgeons Bouley and Ferguson, 
in the course of their memoir on horses' teeth, record 
some important facts about supernumerary teeth. In 
one animal the rows of grinders are said to appear 
double. The facts are given in that particular chap- 
ter in preference to the present one in order that the 
memoir may have a connected reading. 

M. Koche Lubin gives the following account of a 
tooth that he extracted from the upper jaw of a young 
bull ("Le Zooiatre du Midi," February, 1838): 

" On the 14th of April, 1837, I was requested by M. 
Bonhome, who lives near Rhodez, to extract a tooth 
which was growing in the middle of the palate of his 
young bull. The novelty of the thing made me hasten 
to comply with his request. The animal being secured, 
I removed the tooth in the usual way. A very consid- 
erable hemorrhage followed its extraction, which was 
performed with some difficulty on account of the tooth 
being firmly implanted in the palatine arch. It was 
situated at the middle of the median line, and was of 
precisely the same character as tliat of the usual incisor 
tooth of the ox. This is, 1 believe, the only case on 
record, the incisor teeth being wanting in the upper 
jaw of cattle." 



128 SUPERNUMERARY TEETH. 

Human beings, like the lower animals, are now and 
then afflicted with a superfluity of tooth-substance, or 
at least they have supernumerary teeth. John Hunter 
says (" The Human Teeth," p. 53) : 

^' We often meet with supernumerary teeth, and this, 
as well as some other variations, happens oftener in 
the upper than in the lovv^er jaw, and, I believe, always 
in the incisors and cuspidati. 1 have only met with 
one case of this kind, and it Avas in the upper jaw of a 
child about nine months old. The bodies of two 
teeth, in shape like the cuspidati, were placed directly 
behind the bodies of the two first permanent incisors; 
so that there were three teeth in a row, placed behind 
one another, namely, the temporary incisor, the body 
of the permanent incisor, and that sujoernumerary 
tooth. The most remarkable circumstance was that 
these teeth were inverted, their points being turned 
upward and bent, caused by the bone which was above 
them not giving way to their growth, as the alveolar 
process does." 

The following account of cases of third dentition in 
human beiugs is from "Bond's Dental Medicine" 
(p. 310): 

^'TJiircl Dentition, — A number of well authenticated 
cases of partial and even complete dentition, occurring 
in very old persons, are recorded in the books. In one 
instance, given in the 'Edinburgh Medical Com.' (vol. 
iii.), the patient, who was sixty years old and entirely 
toothless, suffered very severely. At the end of twenty- 
one days from the beginning of his sufferings, however, 
he was compensated by the appearance of a complete 
set of new teeth. 



TIIIIID UENTITIOXS FATAL. 129 

"With regard to tlie constitutional effects of this 
abnormal dentition, Prof. Harris, who relates two 
cases as having occurred under his own observation, 
says: 'It seems tliat the efforts made by nature for the 
production of a third complete set of teeth are usually 
so great that they exhaust the remaining energies of 
the system, for occurrences of this kind are generally 
soon Ibllowed by death.' " 

Retention of Deciduous Teeth. — Miss A. B., 
aged twenty years, has never shed her deciduous 
second molars. They are sound and healthy, except 
one. The first bicuspids have been erupted; the 
second have not. Would it be proper to extract the 
temporary teeth ? — M. A. 

In answer to M. A., in the November, 1881, num- 
ber of the Dental Cosmos, I would reply that from 
my experience it would be poor practice to extract 
healthy deciduous molars at that age, merely because 
they were deciduous, and when 7iothing else indicated 
such treatment. I have met Avith many such cases. 
Sometimes only one or two of the molars are retained ; 
at other times three or four. I know of two sisters, 
over forty years of age, who have each their four 
deciduous second molars, and every one perfectly 
healthy. — Stormont. \ 



CHAPTER VII. 

HORSES' TEETH UXDER THE MICROSCOPE. 

The Dentinal Tubes, Enamel Fibers, and Cemental Canals De- 
scribed and Contrasted. 

Prof. Richard Owex's description of the micro- 
scopical appearance of horses' teeth, like the extracts 
already made from liis works, is botli interesting and 
profound. The teeth described are illustrated in the 
second volume of the " Odontography," the section of 
the molar being magnified three hundred linear diam- 
eters; that of the incisor, however, is not magnified. 
In the first volume (pp. 576-7-8) Prof. Owen says : 

"The body of the long molar teeth of the horse, 
consists of columns of fine-tiibed, unvascular dentine, 
coated by enamel, which descends in deep folds into 
the substance of the teeth. The enamel is covered 
by cement, thickest in the interspaces of the inflected 
enamel-folds and upon the crowns of the molars, where 
it is permeated by vascular canals, thinnest on the 
crowns of the canines and incisors. At the roots of 
these teeth, and on those developed from the w^orn- 
down molars, the dentine is immediately invested by 
cement. 

'^ In a vertical section of the incisor, as in Plate 136, 
Fig. 11, the pulp-cavity, contracting as it approaches 



TUBES DIClIUTO.MOrSLY BILVXCIIED. Vol 

the vertical enamel-fold, divides near the end of tliat 
fold, and extends a little way between it and the 
periphery of the incisor, or leaves a few medullary 
canals and a modified thin tract of irregularly formed 
dentine between the reflected and the outer coat of 
enamel, but rather nearer the former. Above this 
tract", near the summit of the crown, the dentinal tubes 
13roc3ed in a nearly vertical direction, with a gentle 
sigmoid primary flexure, where they diverge from the 
perpendicular. Lower down they diverge in opposite 
directions, curving from the remains of the pulp- 
fissure toward the outer and the inner enamel, and are 
described by Rotzius as being in the form of the Greelc 
e; but the course of two distinct series of dentinal 
tubes, and not of a single tube, is illustrated by this 
comparison. When the pulp-cavity conies single and 
central, as at the lower half of the tooth, the tubes 
diverge to the periphery, with one principal primary 
curve, convex toward the crown. Each tube is bent 
in minute secondary gyrations to within a short dis- 
tance of its peripheral termination, where it is much 
diminished in size, and is dichotomously branched. 
The tubes at their beginning form the upper calcified 
tracts of the pulp-cavity, which usually retain some 
remnants of that vascular receptacle in the form of 
medullary canals, and are strongly and irregularly 
flexuous before they fall into the ordinary primary 
curves. These tubes, proceeding toward the inner 
reflected folds of enamel, are more vertical than the 
tubes going to the periphery. 

" A transverse section of the incisor of a young horse 
or ass, taken across the part marked a in Fig. 11, shows 
a long ovat island of vascular cement in the center, 
bounded by a border of enamel, with an irregular ere- 



132 HOIlSEo' TEETH UXDER THE MICROSCOPE. 

nate edge next the cement, and an even edge next the 
dentine, which is here clearly seen to be divided into 
an inner and an outer tract by an irregular series of 
the vascular canals continued from the summit (>f the 
jDul^^-cavity, and by the irregularly tortuous dentinal 
tubes, which, with the canals, indicate the last con- 
verted remnant of the pulp in this part of the crown. 
The inner tract of dentine next the island of enamel 
is well defiiic'd, and a little broader than ti]e secretion 
of the enamel itself, and shows the extremities of the 
tubes cut transversely, wiiich, as before observed, were 
at this point directed chiefly in the axis of the incisor 
toward the working surface of the crown. The tubes- 
in the outer tract of dentine, inclining more toward 
the sides of the tooth, are more obliquely divided, and 
at the ends of the section they are seen lengthwise, ele- 
gantly diverging toward the sides of the section. This 
tract of dentine is bounded externally by a layer of 
enamel, one-sixth part thicker than that forming the 
central island; and the enamel is coated by an outer 
layer of cement, of its own thickness at the sides, but 
thinning off at the two ends of the section. The den- 
tinal tubes proceeding from the residuary pulp-tract 
make strong and irregular curvatures, diverging to 
include the divided areas of the vascular canals, and 
in the outer layer, at one side of the section, they de- 
scribe strong zigzag curves at the middle of the outer 
division of the dentine. 

"The diameter of the dentinal tubes at their central 
and larger ends is pretty regular, about -goVotli of an 
inch ; at the middle of their course, -g-oVo-tb of an inch, 
thence decreasing, and very rapidly, after the terminal 
bifurcations begin. The tubes are separated from one 
another by intervals varying between once and twice 



THE CURVES OF THE DEXTIXAL TUBES. 133 

their thickness. In some parts of the dentine of the 
incisor they are niore closely crowded together, espe- 
cially near their origin from the pulp-cavity. Their 
secondary gyrations describe a curve of about y^oth 
of an inch in length. These subside in the slender 
terminations of the tubes, which bifurcate dichoto- 
mously once or twice, and send off small lateral 
branches near tlie enamel. The small lateral branches 
are chiefly visible in the peripheral third part of the 
tubes, and are sent off at very acute angles, except in 
the strongly and irregularly bent origins from the 
pulp-tract. I have never seen these small branches of 
the dentinal tubes terminating in radiated cells, like 
those of cement and bone, as Retzius describes; but 
the peripheral smallest branches near the enamel occa- 
sionally dilate into corpuscles much more minute 
than the radiated cells, as they do in the teeth of most 
quadrupeds. 

" The dentine, as seen in a longitudinal section of 
the crown of a molar, by a magnifying power of three 
hundred linear dimensions, is figured at a, Plate 137. 
The tubes are here separated by rather wider inter- 
spaces than those of the incisor, and do not decrease 
in size so rapidly. The convexity of tlie terminal l)end 
of the tubes is turned toward the summit of the crown. 
In the incisor, the clear dentinal cells are very small 
near the peripheral part of the dentine^ but increase in 
size as they approach the pulp-cavity. They are of a 
sub-circular figure, with bright, transparent lines. 

"The central cement in the crown of the incisor is 
permeated by vascular canals, separated by intervals of 
from two to three times their own diameter, directed 
in the middle of the substance in the axis of the tooth, 
but diverging like rays obliquely toward its periphery. 



134 horses' teeth uxder the microscope. 

The clear substance forming the walls of the canals is 
arranged in concentric layers, the thickness of the 
walls being about equal or rather less than the area of 
the canal. The radiated cells, generally of a full oval, 
sometimes of an angular form, are chiefly dispersed in 
the interspaces of the vascular canals, and with their 
•long axis parallel with the plane of the layers of the 
coats. The finer system of tubes radiating from the 
cells, and corresponding by minute branches from the 
vascular canals, freely intercommunicate. In the 
peripheral cement of the incisors examined by me, I 
found no vascular canals, but only the radiated cells, 
and the fine tubuli which I have called 'cemental,' 
and which traverse the cement at right angles to its 
plane, and communicate with the tubes radiating from 
the cells. These are more usually elliptical than in 
the thicker central cement, their long axis being par- 
allel with the borders of the cement. They are most 
abundant next the enamel, and rarely encroach upon 
the clear peripheral border of the cement. The exte- 
rior coronal cement of the molars (Plate 137, c), is as 
richly permeated by vascular canals (v v), as is the 
central cement of the incisor. 

*'The enamel-fibers of the horse's incisor are very 
slender, not exceeding twice the diameter of the denti- 
nal tubes. They extend, with a single sigmoid curve, 
through the entire thickness of the layer, contiguous 
fibers curving in opposite directions. The peripheral 
border, or that next the cement, is everywhere indented 
with hemispherical pits from ji^f^\ to -g-oVo^^^ ^^ ^^ 
inch in diameter, from four to six of the radiated cells 
of the cement being ofien clustered together in the 
larger depressions. The inner or dentinal border is 
nearly even and straight; here are seen the short 



CLEARNESS OF THE EXAMEL- FIBERS. 135 

cracks or fissures extending into the enamel. The 
fibers are rather more wavy in the thicker enamel of 
the molar teeth (Plate 137, d), 

"If the enamel is viewed in sufficiently thin sec- 
tions it is free from those wavy, dusky markings which 
are produced by the more tortuous fibers of the human 
enamel; and I have been unable to distinguish any 
transverse strife in the fine fibers of that tissue in the 
horse. The appearance of such is given by thicker 
sections of the enamel-fibers taken obliquely across 
them, and is produced by the cut ends of the fibers." 



CHAPTER VIII. 

THE PATHOLOGY OF THE TEETH. 

Importance of the S abject. — Caries caused by Injlamed Pulps, 
Blows, Virus, and Morbid Diathesis — Supernumerary Teeth 
and other Derangements. — Trephinino- the Sinuses. — Gutta 
Percha as a Filling. — Cleaning the Teeth. — A Diseased Fos- 
sil Tooth. 

The importance of the study of the pathology of 
the teeth is self-evident, for they not only bear impor- 
tant relations to the general system, but, like all other 
parts of it, are subject to disease and derangement. 
The fact that disease of tlie teeth is involved in more 
or less mystery, is an argument in favor of the study 
of the subject, for, to use Surgeon Gamgee's words, 
it is a '^duty to study the laws of disease as well as 
health," and "it is praiseworthy to dive into the mys- 
teries of the origin of" diseases as well as monsters. It 
is probably not too much to say that, to the successful 
surgeon, knowledge of the diseases and derangements 
of the teeth is indispensable. 

In order to facilitate the study of and cast light on 
the subject, I have brought into juxtaposition, as it 
were, a summary of the views of a few able men in 
regard to the cause of caries, &c., which, better still, is 
followed by the reports of well-known surgeons, who 
give the results of their experiences in detail. 



DECAY, EXOSTOSIS, AXD ABSCESS. 137 

Dr. G. A. ]\[ills says that when the tone of a tooth 
can be brought to the point of resistance of the in- 
flammatory process, dentists will have gone a long 
Tvay in providing against the etfects of caries. The 
dentine decays faster than the enamel. 

Prof. Owen says a tooth lias no inherent power of 
rej^aration ; that in gi-owing teeth, with roots not fully 
formed, the cement is so thin that the Purkinjeim 
cells are not visible. It looks like a fine membrane, 
and has been described as the periosteum* of the 
roots. It increases in thickness with the age of the 
tooth, and is the seat and origin of what are called 
exostoses of the roots. These growths are subject to 
the formation of abscesses and all morbid actions of 
true bone. Of a diseased fossil horse^s tooth he says : 

" But the cavity had evidently been the result of 
some inflammatory and ulcerative process in the origi- 
nal formative pulp." 

Dr. Boon Hayes says : 

"I think it would not be diflScult to prove that 
caries of the teeth more frequently proceeds from in- 
flammation beginning in the pulpal cavity than from 
any other cause." 

Dr. Robley Dunglison says : 

"The most common causes of caries are blows, the 
action of some virus, and morbid diathesis." 

* Surpfcon John Hughes says : " The periosteum of the teeth 
is not supplied with blood in the way the same membrane iu 
other parts of the body usually is. It is supjdied by means of 
vessels coming frpm the pulp of the tooth." If this is true, then 
it would be easy for inflammation to be conveyed from one to 
the other. 



138 THE PATHOLOGY OF THE TEETH. 

"Odontoiiecrosis" is defined by him as "dental gan- 
grene," and "Odontrypy^^ as "the operation of perfo- 
rating a tooth to evacuate the purulent matter con- 
fined in the cavity of the pulp" (pulpal cavity). 

Prof. William Percivall, referring to two diseased 
grinder teeth (horses'), says: 

" They seemed to have been cases which had origi- 
nated in internal injury." 

Surgeons Bouley and Ferguson say: 

"In explaining caries of the teeth, we cannot invoke 
the aid of inflammation and the modifications which 
it induces in the tissues it attacks; nor can we say 
that inflammation implies an active circulatory move- 
ment, an afflux of liquid, an alteration, nervous de- 
rangement, &c." 

Possibly the gentlemen were not aware of the in- 
flammation that Prof. Owen says may exist "in the 
original formative pulp," and of that of "the pulpal 
cavity" — the pulp in the cavity of a full-grown tooth — 
mentioned by Drs. Hayes and Dunglison. Are not 
such inflammations liable to be j)roduced by colds or 
violent shocks? 

Prof. George Varnell, who believes caries of the roots 
of horses' teeth is usually caused by external violence, 
says : 

"Inflammation of the alveolo-dental periosteum 
would tend to this result (caries of the roots). When 
the nutrition of any part of a tooth becomes arrested, 
decay is likely to follow. When caries begins from 
within, it is due to arrestation of nutrition, arising 
perhaps from disease of only a part of the central pulp 



NATURE BARRICADING DISEASE. 139 

of the tooth ; if from without, it will arise from the 
periodontal membrane where it meets the gum." 

Dr. John Tomes thus describes the conservative ac- 
tion of nature (barricading disease, as it were) when a 
tooth is affected with cai'ies (•• Dental Phj^siology and 
Surgery"): 

"When a portion of dentine has become dead, it is 
circumscribed by the consolidation of the adjacent liv- 
ing tissue. The tubes, becoming filled up, are ren- 
dered solid, and the circulation is cut off from the dead 
mass. This consolidation does not go on gradually 
from without inward, keeping in advance of the decay, 
but occurs at intervals. It seems that successive por- 
tions of dentine lose their vitality, and that the contig- 
uous living portions become consolidated." 

Prof. M. H. Bouley and Surgeon P. B. Ferguson are 
the joint authors of a memoir on horses' teeth, which 
fills thirty or more pages of "The Veterinarian" for 
1844. The substance of the part which relates to the 
pathology and dentistry of the teeth is as follows : * 

"i. Anomalies in the Number of the Teeth. — Some- 
times, but very rarely, we meet with supernumerary 
grinders in the horse. The anomaly may be caused 
by the persistence of the temporary teeth, the develop- 
ment of abnormal teeth on one or both sides of the 
arcades (rows of teeth), and the cutting of a greater 

* The phraseology of Messrs. Bouley and Ferguson's memoir 
has been more or less chanc^ed and the matter somewhat con- 
densed and rearran<^ed. The suroeons' golden ideas deserve to 
be set forth in clearer and more forcible language than they re- 
ceive at their own hands, and it is believed that some improve- 
ment has been made. 



140 THE PATHOLOGY OF TH^ TEETH. 

number of permanent teeth than should naturally 
exist. In the latter case it is necessary to admit the 
existence of a greater number of dental bulbs than is 
normal. We saw some time ago, at the consultation 
of the Veterinary College in Alfort,* a horse which, to 
use the words of its owner, ' had a double row of teeth 
in the upper jaw.' 

'^Sometimes the supernumerary tooth is situated in 
one or the other jaw, in front of the normal range of 
grinders, without having a corresponding tooth in the 
opposite jaw ; at other times it is situated either within 
or without the arcade. The latter anomaly is caused 
more frequently by the deviation of a normal than by 
the addition of a supernumerary tooth. In the first 
instance it is not long before mastication is interfered 
with. The tooth, by its growth, which is not counter- 
acted by wear, finally reaches the opposite jaw, lacera- 
ting the mucous membrane and contusing and some- 
times fracturing the bone itself. In the second in- 
stance, the tooth, if within the arcade, is an obstacle 
to tlie tongue; if without, to the cheek. Besides these 
evil effects, supernumerary teeth cause irregularity in 
the arcades, and consequently prevent the exact appo- 
sition of the normal teeth. They interfere also with 
the action of the lower jaw. Hence irregularity in the 
friction and wear of the teeth follows, the result being 
that the performance of the all-important function of 
mastication is almost stopped. 

";2. Anomalies in the Form of the Arcades. — The 
upper rows of grinder teeth form two curves, opposed 
by their concavities, while the lowxr rows form two 

* A city of France — Prof. Boiiley's home. Surgeon Ferguson, 
an Englishman, was attached to the Paris British Legation. 



DERANGEMENTS OF THE GllIXDERS. 141 

nearly straight lines, which converge as they descend 
toward the symphysis of the clun. These (the curves 
and lines) may be, owing, in some cases, to congenital 
conformation, very irregular. Sometimes, in fact, the 
curves of the upper jaw are effaced ; at other times, 
and most frequently, the lines of the lower jaw are 
incurvated within the upper arcades. The deformities 
may exist singly or together. The result is that, in 
the approach of the jaws, the relation is not identically 
established between the surfaces of friction, and the 
result of this, in turn, is an irregularity of wear and an 
abnormal development of the borders of the tables (the 
crowns of the teeth), within in the lower jaw, without 
in the upper. 

'"'J. Exuberance of partimdar parts of the Dental 
Apparatus.— {A.) The upper grinders are wider than 
the lower, so that in order to cause friction in their 
entire thickness, a lateral movement of the lower jaw 
is required. Sometimes, perhaps because the move- 
ment is not effected throughout the entire limits of 
the segment of the circle, the outer borders of the 
upper teeth do not wear sufficiently, and therefore 
become elevated and sharp. At other times it is the 
inner borders of the lower teeth that project. In 
the former case the cheeks suffer; in the latter, the 
tongue. 

"In rare cases the tables, w^hich present a normal 
inclination inverse in the two jaws, at length form 
planes very oblique. The obliquity is sometimes so 
great that the internal borders of the lower teeth are 
very elevated, whi'e the external is almost level Avith 
the gums. The inverse effect manifests itself at the 
upper jaAV. The consequence is that the half-masti- 
cated food slips into the pouch of the cheek. 



142 THE PATHOLOGY OF THE TEETH. 

" There is in the miise-um of the College at Alfort a 
horse's head in which this deformity may be seen in 
its greatest degree. The tables of the teeth at the right 
side form ])lanes so much inclined that they close 
together like the blades of shears. As there was no 
friction to wear the teeth down, they grew to the hight 
of three inches. The fonrth and fifth teeth of the 
right side of this rare anatomical specimen are absent. 
Perhaps they were carious. The rarefied and spongy 
tissue of the socket-bones indicate the seat of an alter- 
ation — probably caries — which was the point of depar- 
ture of the general tumefaction. The last tooth, by 
its oblique direction toward the empty sockets, indi- 
cates that the loss of the teeth occurred during the life 
of the animal, some time perhaps prior to its death. 
The defect of the right side doubtless forced the ani- 
mal to use the left for the purposes of mastication. In 
such ca^es the teeth that do not wear grow till they 
reach their respective opposite jaws, even when those 
at the opposite side of tlie mouth are in exact con- 
tact, an anomaly never produced in the normal state. 
The function of mastication operates according to the 
obliquity of contact, and a parallelism is established 
by friction between the tables which normally would 
be superposed. 

" This appears to us to be the only interpretation of 
the facts, and we have observed two analogous exam- 
ples in living horses, but we did not think to ascertain 
whether the deformity of an entire arcade was owing 
to defect of a grinder or to disease of the bone. The 
solution of the question would be an important acqui- 
sition to the science of dental pathology. 

" (B.) There is another kind of deformity of the 
arcades not very uncommon. The lower teeth wear 



"GUMMING IT.'* 143 

out more rapidly than the upper, the cause of which 
is perliaps owing to the superiority of the latter in size 
and strength. The crown surface of the lower rows 
is slightly concave, the upper rows slightly' convex. 
The result is that the lower center teeth are sometimes 
worn to their sockets, which renders the mastication 
of hard food impossible. At first, however, tliere is 
no interference with mastication, and it is usually oniy 
in old age that the dcfoj-mity reaches its worst stage. 
There is no remedy for the defect, hut its progress 
may he retarded by the use of soft food, '^ 

" (C.) Lack of regularity in the length of the rows 
becomes the cause, in horses a little advanced in age, 
of a peculiar deformity in the first upper and the last 
lower grinders. Generally the upper range passes that 
of the lower by some lines, the first upper grinder lap- 
ping over; but sometimes the case is the reverse, the 
last lower grinder projecting beyond the last upper. 
The projecting part of the tooth grows till it reaches 
the opposite jaw, when, unless it is filed or chiseled off, 
the most serious consequences will follow. 

" ( D.) When a tooth is entirely deficient, the oppo- 
site tooth grows till it fills the void ; then, no remedy 
being applied, the work of destruction begins. If a 
tooth is only partly deficient, no matter whether it be 
from fracture, caries, or arrestation of growth, it is 
gradually destroyed by the opposite tooth. AVhen it 
is the first upper grinder that is deficient, the first 
lower acts on the palatine vault like a bnttering-ram. 
*I have seen,' says Solleysel (1GG9), *a mule that had a 
lower grinder of extreme length, the upper tooth being 
absent. The palate was pierced to the thickness of a 

* The italicized words arc mine. — G. 



144 THE PATHOLOGY OF THE TEETH. 

finger, which caused the animal great difficulty when 
he drank/ 

•^^. Caries of the Teeih. — The grinder teeth of horses 
are more frequently affected with a profound alter- 
ation of their substance than is generally believed. 
The disease is called Caries ; it may not, however, be 
strictly analogous to caries of the bones, for the bones 
are vascular, while the teeth have neither vessels nor 
nerves. Caries of the bones implies an active labor, in 
which the vascular apparatus plays an important part. 
It is a phenomenon of interstitial suppuration, under 
the influence of the inflammation which has set the 
capillary system of the organ in play. In explaining 
caries of the teeth, however, we cannot invoke the 
aid of inflammation and the modifications it induces 
in the tissues it attacks; nor can we say that inflam- 
mation implies an active circulatory movement, an 
afflux of liquid, an alteration, nervous derangement, 
&c. If the teeth are living, the laws which govern 
their vitality are entirely unknown to us.* How, then, 
penetrate into the secrets of the alterations which they 
undergo, when the conditions of their normal existence 
are enveloped in obscurity? JS^either is it possible to 
resolve the question as to the essence of the affection 
designated by the name of caries. Therefore we design 
to make known only the different modes of expression 
relative to it 

" Caries usually attacks the dentine of the crown of 
the tseth, between two folds of enamel. The dentine 
becomes of a brownish or blackish color, and dissemi- 

" It should be borne in mind that the above viaws were enun- 
cUvted more than a third of a century ago. The gentlemen 
pro'jably say too much. Compare with Dr. Hayes's views as 
recorded on pag-e xxii. 



DENTIKE DECAYED, ENAMEL SOFTEXED. 145 

nates an ofTensive odor sid generis, wliicb perhaps is 
as nuicli owing to the putrefaction of the saliva iu the 
cavity as to the decomposition of the dentine. The 
decay progresses between the folds of enamel, and the 
latter substance, notwithstanding its great density, 
takes on the blackish tint of the dentine and becomes 
sufliciently softened to allow of its being cut by a sharp 
instrument. Sometimes even the planes of the enamel 
dissolve, and then the cubic mass of the tooth becomes 
so much decayed that it resembles a deep cavity, the 
parietes of Avhich are formed by the planes of enamel 
laid bare by the caries. Sometimes caries attacks the 
tooth on one of its four side surfaces; at other times 
the root is attacked ; but wherever its primitive seat 
may be, the blackish veins always extend into the den- 
tine, and thus isolate the lilies of enamel. 

" Carious teeth rarely preserve either their form or 
volum.e. They become hypertrophied at their roots, 
but the effect does not manifest itself until the disease 
— having undermined all the layers of dentine in its 
course — has penetrated the root. When the caries has 
penetrated to the socket, the alveolo-dental membrane 
becomes irritated by the contact of decaj^ed matter, 
increases its secretion, and deposits a thick layer of 
osseous matter in the circumference of the root of the 
tooth, which concretes irregularly upon the normal 
layers. The deposition does not, however, always take 
place iu the circumference of the root, for in some 
cases it is only at isolated places that the secretion of 
the alveolo-dental membrane occurs. Then the root 
presents a succession of lar^e osseous tubercles, which 
bar the tooth iu, rendering its extraction very difficult. 
When the irritation has been from the first sufficiently 
active to cause suppurative inflammation, the normal 
7 



146 THE PATHOLOGY OF THE TEETH. 

secrGtion is suspended, and pus collects in the alveolar 
cavily, around the root, which then ceases to augment 
in volume. In the former case, however, the root, 
augmented in volume, can no longer be contained in 
the cavity, the walls of which are expanded by its 
wedge-like action, which accounts for the extreme 
pain in the adjacent parts, and tlie particular altera- 
tions in the osseous tissues. The osseous tissue tume- 
fies, and suppuration is established in the interior of 
the socket; the membrane is partly destroyed, which 
leaves the bone bare and exposed to the maceration 
of pus and the irritating contact of the morbid matter 
that continually penetrates into the socket by the 
dental fistula; the bony tissue sphacelates upon the 
borders, where its substance is the most compact, and 
its spongy tissue, which forms the bottom of the cavity, 
soon becomes the seat of an interstitial suppuration — 
that is to say, in fact, of veritable caries. The swell- 
ing may now extend throughout the entire extent of 
the maxillary bone, and thus render mastication im- 
possible. 

" It may now be seen, an alteration of this nature 
being set in action, how the phenomena of the nutri- 
tion of bone may be modified in their direction to the 
point of producing osteosarcoma. 

" Caries of the roots of any of the lower grinders may 
be complicated with lesions of the jaw, for the lower 
jaw is continuous in its entire extent. In the upper 
jaw the phenomena are in principle the same, but the 
contiguous nasal cavities and sinuses induce complica- 
tions the study of which is imiwrtant. It is also im- 
portant to take into consideration the position of the 
diseased tooth, in order to appreciate the extent of the 
lesions which a simple caries may produce. 



COMPLICATIOXS WITH NERVES, SINUSES, ETC. 147 

**'Tlie two first upper grinder teeth are separated 
from the nasal cavities by a thin bone, which is easily 
eaten through. When caries attacks their roots, the 
inflammation extends itself to the membrane lining 
these cavities, and a perforation of the osseous partition 
may establish communication between the mouth and 
the nose. Under the influence of interstitial suppu- 
ration, the osseous membrane is destroyed to an enor- 
mous extent. The aliments pass through the dental 
fistula into the nose and arc expelled by it along with 
the product of the morbid secretion of the pituitary 
membrane. 

"The tliird grinder is situated near the m-ixillary 
sinuses, from which the root is separated by a thin dia- 
phragm. It deserves to be specially noticed on account 
of an anatomical peculiarity, which renders caries of 
this tooth very much to be dreaded. We refer to the 
position of large fascia (bundles) of the superior maxil- 
lary branch of the fifth pair of nerves, which make 
their exit upon the face by the submaxillary foramen, 
and which are placed immediately over the root of this 
tooth. It is easy to imagine the pain that may follow 
nervous complications in caries of the roots of the 
third grinder. 

" The position of the fourth, fifth, and sixth grinder 
teeth, immediately below the vast maxillary sinuses, 
from which their roots are separated by thin osseous 
partitions, gives to caries of these teeth, and to the 
complications which it induces, a special character, 
which demands that we should speak of it somewhat 
in detail. These teeth communicate with the sinuses 
as easily as the first and second do with the nose; but 
the case is far worse for the horse, there being so little 
outlet for the pus. 



148 THE PATHOLOGY OF THE TEETH. 

"Wlicn the disease has ponotrated the roots, and 
has induced the usual inflammation, the thin parti- 
tii)ns that separate them from the sinuses do not resist 
very long. Destroyed by the dilatory effort of the 
hvpertrophied root and the influence of the caries, the 
altered matters of the mouth have free access into the 
sinuses. Under the influence of their contact, the 
membrane of the sinuses irritates, vascularizes, and 
thickens by a serous infiltration in the early stage. 
Then, the primitive cause of this modification contin- 
uing, the membrane hypertrophies somewhat, and in 
a short time, OAving to its vascular system being richly 
developed by inflammation, large vegetations of the 
nature of polypi are elevated upon it. These, on ac- 
count of the incessant augmentation of their volume, 
fill the sinuses and cause a swelling of their walls. 

"When the membrane of the sinuses has become 
the seat of an abnormal vegetation, an abundant quan- 
tity of purulent matter is secreted, the more liquid 
part of Vviiich drains out through the conduits leading 
to the nasal cavities, while the more concrete part' 
remains in the sinuses. It then, according as it loses 
its serosity, undergoes a transformation, and finally 
displays the aspect of cadaveric grease, which 'it also 
resembles in its repugnant odor. There is a great 
analogy between the disease that causes this particular 
lesion and that of glanders. 

'' Symptomatology . — The first symptom that indi- 
cates a derangement of the dental apparatus is a diffi- 
culty in mastication. The animal, excited by liunger, 
seizes the food with avidity. The motions of the lower 
jaw, however, are made with a sort of hesitation, and 
often only at one side. The imperfectly masticated 
hay, which on that account will not pass through the 



HUNGRY, BUT UNABLE TO EAT. 149 

narrow pharynx, is dropped into the manger in the 
form of cads or flattened pellets. The nose is plunged 
into the feed, over which the animal fumbles and nib- 
bles, but of which it eats little. 

^'Tlie insufficiency of nutrition soon produces a 
baneful effect on the whole economy. The coat tar- 
nishes, becoming dry and staring; the least exertion 
niakes the animal sweat; it is heedless of the whip; 
the mucous membranes become discolored ; the pulse 
weakens, and cold infiltrations sometimes appear in 
the extremities. To see an animal thus suddenly 
transformed, one is apt to mistake the true cause and 
attribute it to the influence of some grave organic dis- 
turbance. 

" These symptoms are common to the different dis- 
eases and derangements of the dental apparatus, and 
are sufficient to lead to a positive diagnosis. The 
diagnosis, however, can only be precisely determined 
when the mouth shall have been examined, for by this 
means we perceive the particular signs of each of the 
alterations that opposes the function of mastication. 
The mouth may be kept open by a speculum oru, or 
even by drawing ont the free portion of the tongue, 
which should be held' by the thumb and the third and 
fourth fingers, the index being placed between the 
inner side of the upper lip and the gum, at the space 
between the grinders and the tushes, while the other 
hand is left free to aid the inspection by taxis. 

"If the derangement be the result of an exuberance 
of a tooth, vicif>us inclinntion or projections of the 
tables, fractured teeth, swollen socket?, &c., the sight 
is ordinarily sufficient to detect it, for the teeth are, 
besides, frequently soiled by the greenish remains of 
food at the affected part, and often even the cheek is 



150 THE PATHOLOGY OF THE TEETH. 

filled witli an accumulation of malgroiind food. The 
mouth should be cleaned with water, iu order that the 
defect may be more plainly seen ; if, however, on ac- 
count of its being situated far back in the mouth and 
the motions of the base of the tougue from side to side 
intercepting the view, its natui-e cannot be discov- 
ered with the eye, it will be necessary to resort to the 
sense of touch. The mouth being held open by the 
speculum oris, or some other firmly-fixed apparatus, 
the fingers should be passed rapidly within and without 
the arcades, but never on them, because of the danger 
of having them crushed : whatever may be the degree 
of forced dilatation of the mouth, there can never be 
much separation of the jaws in the region of the last 
grinders; besides the animal can lessen it by pressure. 

"When the buccal membrane has been excoriated 
by the contact of irregularly-worn teeth, the gums in- 
flamed, the jawbones contused, and the latter sphace- 
late or suppurate, there are some modifications of the 
general symptoms. The animal loses its appetite, 
becomes dull, 'crest-fallen,' and agitated with febrile 
disturbanc3, however little the heart of the inflamma- 
tion may be extended. The saliva, wdiich dribbles 
from the mouth, is stringy, and, when mixed with 
pus, fetid; the mouth is hot and its membrane in- 
jected; there is a turgescence of the gum at the point 
of inflammation; a tumefaction of the bone, with a 
grayish tint at the point where it is denuded and about 
to exfoliate, or else fistulse abut into the heart of the 
suppuration in the spongy tissue of the jaw. 

" Particular Symptoms of Carles.— Qavie^ of the 
grinder teeth is characterized by peculiar symptoms, 
some of which are common to the teeth in general, 
while others belong to some grinders in particular. 



CARIES differe:^t in different teeth. 151 

To give precision to the diagnosis, tlie position of the 
teeth should be taken into consideration. Besides the 
symptoms common to all disorders of the teeth, caries 
in general presents as diagnostic signs — 

'• 1. A fetor very remarkable and sui generis of the 
mouth, and of the saliva which humefies it. 

"2. Dril)bling of an abundant and stringy saliva 
from the mouth. 

".3. Existence on one of tho faces of the tooth, and 
principally upon its crown, either of a blackish spot or 
a large cavity of the same color, according to the ex- 
tent of the disease. 

" 4. The extreme pain that the animal evinces when 
the tooth is struck. 

^^If the disease is of long standing, and especially if 
it has arisen from the side of the root, in addition to 
the foregoing modifications and complications, other 
and more special symptoms manifest themselves. The 
bone tumefies and the animal evinces pain when it is 
pressed by the fingers ; the gums are affected with tur- 
gescence, and bleed from the least contact; all the 
buccal mucous membrane reflects a red tint, and in 
the meantime fever sets in, manifesting itself by all 
its ordinary and general symptoms. 

"Caries of the first and second upper grinders may, 
as alrea'ly explained, be complicated with lesions of the 
nasal cavities. Then the pituitary membrane irritates 
and secretes abundant mucosities, but at one side only, 
with which the food becomes mixed, giving it a green 
tint, but very different from tlie secretions of glanders. 
The case is ^liffercnt, however, in the complications 
induced by caries of the last grindjrs. In fact there 



15;^ THE PATHOLOGY OF THE TEETH. 

is such a close resemblance between the symptomatic 
expressions of the nose following caries of these teeth 
and chronic glanders, that error and confusion are 
common. It is therefore highly important to distin- 
guish these diseases, so essentially different in their 
causes and effects. 

" When the membrane lining the sinuses has become 
diseased, followed by the secretion of pus and polypus 
growths, a jettage is established at one side of the nose. 
It is white, lumpy, and abundant, and is augmented 
in quantity by exercise. The lymphatic ganglions be- 
come engorged and hard, but remain indolent, and 
generally roll under the finger. The zygomatic tables 
of the upper part of the superior maxillary and nasal 
bones swell at the region of the affected sinuses, and 
give a dull sound to percussion.* 

* Prof. Varnel] says : " I am not aware tliat any animal suffers 
from diseases of tlie sinuses of the liead to the same extent as 
the liors3. The sinuses clififer in size in cTifFerent breeds, and in 
individual horses of the same breed. I need scarcely point out 
the necessity of bearing this fact in mind in forming- diagnoses 
of obscure diseases in this region of the head. In certain case.s 
it is not only important to ascertain whether the sinuses contain 
anything abnormal, but also the nature and extent of the mor- 
bific matter. Percussion with the ends of the fingers is one 
mode of obtaining this information. Both sides of the head 
should be struck, and the sound produced in one part compared 
with that in another, and with what it is in health. I would 
recommend students to become familiar with these various 
SJunis. They will be fcmnd to differ, according to the magni- 
tude of the sinuses, in the same way that a large empty cask, 
when struck, will differ in sound from a small one. It will als3 
be well to educate the ear to the character of the sounds pro- 
duced by percussing the sinuses in differently formed heads. 
* -if -r rpjjQ sinuses, strictly speaking, are air cavities, 
which communicate freely with each other, and by means of a 



DELICATE DIAGNOSTIC SIGX3. 153 

"At the first appearance of this group of s3^mptoms 
one is apt to suspicion the existence of glanders, but a 
careful examination will prove it to be unfounded. On 
examining the nasa: cavity, the lining membrane will 
be seen to be smoith, polished, and uniformly rosy, 
with its normal follicular openings, and on unfolding 
the superior wing of the nostril, the salient border of 
the cartilage presents a neat and polished surface, tvitli- 
out any little pimples or morbid tint. Now, we know 
that in glanders, even of the sinuses, which is often 
unaccompanied by cankers or other ulcerations, it is 
in those places certain specific morbid signs may be 
recognized, which, although very superficial and with 
difficulty seen by the eye, are nevertheless of great 
value in the diagnosis. Such, for instance, are the 
peculiar aspect of the salient border of the wing of the 
nostril, with its vivid red tint, the small superficial 
erosions of the hning membrane, entirely hidden under 
the fold of the cartilage, and those small granular pro- 
jections called tubercles. In the jettage from caries 
nothing of this kind exists. There is a marked differ- 
ence in the odor too; in caries the odor is exceedingly 
fetid, while in glanders it is almost null. 

'^ If, after this attentive examination, the surgeon is 
still in doubt as to the specific nature of the nasal dis- 



small opening, with the nasal passage also. This opening is 
situated at the supero-posterior part of the middle meatus, and 
is guarded by an imperfect valve, which, when pressed upon 
from within, either partially or wholly closes it. It may also 
be closed hy the mucous merabrnno being- thickened by disease. 
Internally the sinusss are partially divided into compartments 
by thin osseous nlates, and arn lined by a slightly vascular mem- 
brane, whkli is continuous with that of the nasal passage, but 
is not so thick nor so vascular." 



15 i THE PATnOLOGY OF THE TEETH. 

charge, it will disappear and give place to a true diag- 
nosis when he has examined the mouth and has had 
time to weigh and compare all the facts in connection 
with the case. 

'•It is more especially relative to diseases of the teeth 
that h recognized the truth of the old maxim in sur- 
gery, SuMatd causa, tollitur effectus." (The cause be- 
ing removed, the effect ceases.) 

For putting irregular teeth in order, the surgeons 
recommend the use of a coarse, six-inch file, with a 
handle from twenty to twenty-four inches long. How- 
ever, they say that in their day it was customary among 
the "vulgar" to make the horse cheiv a 7rcsp! The 
process, which they describe, referring among other 
things to the difficulty of getting the rasp precisely 
opposite the projections, is too slow, as they admit, to 
he practicable; besides it is about as difficult to com- 
pel a horse to chew as to compel him to drink. 

For the removal of snpernuraerary grinder teeth or 
the shortening of natural ones tliat have grown beyond 
the level of the other teeth, they recommend the use 
of a chisel and a hammer; two or three well-directed 
blows with the latter are usually sufficient to cut the 
largest tooth in two. The surgeon requires an assist- 
ant or "striker." In the case of the first grinder, the 
blows should be light, otherwise the tooth would be 
loosened in its socket. In the case of the last grinder, 
"it is necessary for the operator to be perfectly master 
of the chisel at the moment of its being struck, for, in 
escaping, it might strike against the velum palati (soft 
palate) and cut it through." 

In performing these operations they prefer tliat the 
horse should be in a standing position, as when in a 



drexchi:d with TOOTii-riLVc;},i!:xTS. 155 

lying position there is danger of his swallowing the 
frugiuenls of the tefeth. If it is necessary, however, to 
cast the horse, they recommend that the head rest on 
the occiput, the operators being tis expeditious as pos- 
sible, to prevent the animal from swallowing the frag- 
ments. As the nose points up, tiie surgeon would 
have to be expeditious indeed in order to prevent the 
horse from being drenched, as it were, with tooth- 
fragments. 

The surgeons next describe an interesting case of 
dental surgery, in the performance of which the bone- 
forceps were used to remove the tushes. They say: 

"It sometimes happens that the fleshy and bony 
structures of tlie mouth are not well proportioned, and 
when the animal is put to work evil consequences re- 
sult, especially if the tongue is too large for the space 
between the branches of the jaws. A remarkable case 
of this kind lately came under our observation in a 
horse owned by the Earl of Clonmel. The animal, a 
rem-irkably tine one, was a very hard * puller,' in conse- 
quence of the bit not coming in sufficient contact with 
the sensitive bars. The space betAveen the tushes was 
too narrow for the tongue, which, after the animal had 
been ridden with restraint by a horse-breaker, was cut 
nearly through at each side. The consequence was the 
tongue became swollen to an enormous extent, and 
as the tushes increased the irritation, their removal 
became necessary. They were cut off to a level with 
the gums with the bone-forceps, the tongue was scari- 
fied and bathed with a cold lotion, and the animal was 
fit for work at the end of a week. 

"Perhapstat first it may seem better practice in such 
cases to extract the tushes entirely. But when the 



156 THE PATHOLOGY OF THE TEETH. 

lengtli and obliquity of their roots and the fact of their 
being situated in tlie weakest part of the jaw are con- 
sidered, it is plain that such a procedure would in all 
probability be followed by the most serious results, 
such as fracture of the jaw, osteo-sarcoma,s &c., the 
formor having happened under our own observation." 

The surgeons recommend (as any intelligent person 
would) the removal of supernumerary or abnormal in- 
cisor teeth. AVhen the tooth is without the normal 
range it interferes with the prehensile function of the 
lips; when within, it interferes with the tongue. The 
former, they say, may either be cut off with the bone- 
forceps or extracted. In the latter case, however, they 
prefer to cut them off, but admit that some teeth re- 
quire extraction, for which the use of the crank-forceps 
is recommended. 

The Treatment of Caries is the next subject consid- 
ered. '' The only remedy for caries," the surgeons say, 
"in the great majority of cases, is the extraction of the 
tooth. If we were called on to treat the disease at its 
beginning, cauterizing the black spot would check its 
progress; but when the dental bulb has been attacked, 
the extraction of the tooth is the only remedy." 

The instrument recommended for extracting teeth 
is the forceps, and under ordinary circumstances, the 
surgeons say, fracture of the jaws ought not to occur. 
They mention as. useful instruments the key invented 
by M. Garengeot, the mouth-screw by M. Plasse, and 
the lever-forceps by Prof. Simonds, but say : 

"Instances occur in which the carious tooth cannot 
be seized by any of these instruments. For example, 
when the last upper grinder is diseased, it is sometimes 



THE POWER OF THE TOXGtJE. 157 

impossible to dilate the mouth sufficiently to slide the 
instrument between it and the corresponding lower 
tooth. Besides, the tongue, however firmly it may be 
held outside the mouth, has still the power to displace 
the instrument by the energy of the undulatory move- 
ments at its base. Again, the back grinders, having 
ordinarily shorter bodies than the others, afford less 
hold for the instrument. In some cases they afford no 
hold at all, as their bodies are worn almost to a level 
with the gums. 

^* Lastly, in some cases the exostosis of the root of 
the tooth is so great that it is, as it were, wedged in 
the socket, and resists all efforts to extract it. What 
is to be done ? The disease may lead to grave local 
complications and dangerous general disorders. In 
such a case we would recommend trephiniug the dis- 
eased sinus and punching the tooth mto the mouth. 
This operation being very unusual, and the observance 
of some rules requisite for practicing it, we will con- 
sider it somewhat in detail. 

"If, as sometimes happens, the swelling over the 
sinus is indistinct, it would be well to be guided by a 
prepared head, in order to apply the trephine in the 
exact place, which is above the diseased root. A large 
V or crucial incision should be made, and the trephine 
manipulated till the sinus is laid open. The opening 
should be extensive rather than confined; it is more 
convenient to apply upon the parietes of the sinuses 
three crowns of the trephine, tangent reciprocally at 
their circumferences; then, by the aid of a sharp in- 
strument and a small hammer, the angles may be re- 
moved. 

"As soon as the mucous membrane of the cavity has 
been laid bare, the change it has undergone may be 



158 THE PATHOLOGY OF THE TEETH. 

seen, and also the vegetations springing from it. At 
the bottom of the sinus, toward the alveolar border of 
the ja\?, among the vegetations, is a hard, granulated, 
dry surface, resistant to the touch, of a grayish tint, 
and analogous to sphacelated bone. This is the sum- 
mit of the root of the tooth. 

^' The surgeon then arms himself with an iron punch, 
rounded at the point, which he applies to the root in 
the sinus, and ha\'ing further separated the jaws by a 
few turns of the specukim oris, commands an assistant 
to strike shorty hard blows, the surgeon looking at the 
tooth to see the effect of each blow. Usually the tooth 
soon gives way, and falls into the mouth generally in 
two fragments, according to the direction of the caries. 
Sometimes, however, from the length of the tooth, it 
cannot be punched entirely into the mouth, being 
stopped by the opposite lower tooth; but it may be 
wrenched out with a pair of long pincers, the handles 
of which should be separated to increase the power of 
the operator. When the operation is terminated, the 
vegetations of the mucous membrane, as far as they 
can be reached, must be excised. To stop the hem- 
orrhage, and to modify the state of the membrane, 
pledgets of tow, moistened with a diluted solution of 
nitric acid, or some other caustic, should be applied. 

"It is really extraordinary with what rapidity the 
structural breaches resnlting from this operation are 
restored by the reparatory efforts of the organic econ- 
omy. The first time wo performed the operation we 
doubted the animal's recovery. The sinuses, laid open 
by a breach nearly two inches and a half in diameter, 
communicated with the mouth by an enormous open- 
ing, the root of the tooth having acquired nearly three 
times its normal volume. The lining membrane of 



TREATMENT AFTER TREPHIXIXG. 159 

the maxillary siiiuse.>, and the frontal also, had suffjrod 
the transformation already described to its greatest 
degree. And, finally, it required efforts almost beyond 
belief to loosen the tooth and force it from its socket. 
Still the animal made a good recovery. 

" Tiie treatment following the operation should bo 
a? follows: Assiduous attention to cleanliness is nec- 
essary from the first. . On the lirst day the animal 
should be deprived of all solid or fibrous food; in fact, 
a little thin gruel is all it requires, and the mouth 
should be gargled with an acidulated fluid even after 
its use. The fluid may be applied with an ordinary 
syringe. Bleeding is often required, the quantity of 
blood to be abstracted depending on the energy of the 
reaction following the operation. 

" On the day after the operation the dressing should 
be raised. The interior of the sinus, cauterizad with 
nitric acid, reflects a blackish tint. The odor is repug- 
nant, and there are generally some remains of putrid 
alimentary matters, mixed with clots of blood, in the 
sinus. Detergents, such as Lebarraque's chlorinated 
solution of soda, mixed with a gentian wine, should be 
injected into the sinus and the mouth cleaned with 
acid gargles; a Arm pledget of chlorinated tow should 
be introduced into the socket, to prevent anything 
passing from the mouth to the sinus. The regimen 
should consist of gruel only, the gargles to be used 
often during the day. 

*' On the second day the borders of the sinus will be 
a little swollen. Reparatory work has begun in the 
cauterized membrane; the eschars detach themselves, 
exposing a rosy surface of favoralde aspect to the view. 
The odor is tess repugnant. Continue the aromatic 
detergent injections, the same food, with the addition 



160 THE PATHOLOGY OF THE TEETH. 

of a little bran, and gargle often. As suppuration be- 
gins to establish itself, the dressings should be renewed 
two or three times during the tj\'enty-four hours. 

"It is not our intention to indicate the progress of 
the wound and the attention it demands from day to 
day. The tumefied bones and other structures in the 
region of the wound proportionally lessen, and the 
membrane of the sinus takes on a uniformly rosy tint 
and the glistening, humid aspect proper to a mucous 
membrane. The nasal flux finally ceases, the matter 
that may be secreted finding an outlet through the 
alveolus into the mouth. The opening made by the 
trephine contracts itself by degrees, but in extreme 
cases, like the one we have described, it is never suffi- 
cient to entirely repair the structures cut away. It 
may be hidden, however, by a leather or metallic plate, 
attached to the check of the bridle." 

The surgeons claim that the resort to this severe 
mode of extracting teeth is justified by the success of 
the operation and its concomitant results, namely, the 
advantage of injecting the sinuses and preventing un- 
healthy secretions by them, and the stopping of the 
discharge from the nose, which had aroused suspicion 
of glanders. They further say — and a better argument 
in favor of veterinary dentistry could not well be ad- 
vanced — that they believe glanders is often caused by 
the neglect of diseased teeth, and "that the modus 
02JerancU of its production in such cases may be ex- 
plained on the ground of the absorption of pus by the 
constitution." 

Of trephining the sinuses they further say: 

"We have treated many cases of caries successfully 
by simply trephining the frontal and maxillary sinuses 



CARIES OF THE SOCKET BOXES. 161 

and injecting detergents; bnt in a fiir greater number 
the treatment has been unsuccessful/^ Yet we believe 
that if, in addition to trephining, the teeth had been 
extracted, and a couimunieation establi^iied between 
the sin as and the nioutli, the results would have been 
more favorable. 

"Monsieur Delafond, in his niemoii* on the evulsion 
of the teeth, pubiislied in 1831, says the operation of 
trepbining is only practicable in the case of the three 
first grinders, it being necessary in the case of tlie three 
last to make an incision through the zygomatico-maxil- 
laris muscb and the nervous plexus which is formed 
on iL We, on the contrary, claim that the fifth pair 
of nerves will l>e injui*ed in oix'rating on the tbree first 
teeth, but that there will be little injury to the muscle 
in the case of the three last" 

The memoir concludes as follows: 

*' Caries Attacking the Maxillary Bone after tlie Ex- 
traction of the Teeth, — When caries of a tooth has in- 
duced consecutively interstitial suppuration of the 
spongy tissue of the socket, it is possible that, even 
after the extmction of the tooth, the disease may at- 
tack the bone. Then, more than ever, may we dread 
the tumefaction of the tissues and sarcomatous altera- 
tions, which are ordinarily the result of persistent sup- 
puration in the areola} of the spongy substance of the 
bones. To prevent these dangerous consequences, the 
socket should be cauterized with the actual cautery, 

* " Sinnses that may have formed by tlie matter from r.b- 
Bcesses io the alveolar proeessos eating- its Avay throucrh tlie wall 
of the alveolus, and wlnVli may o\-)Qxi cither on some part of the 
face or within the mouth, are seldom treated with the success 
one could dosir'^." — Prn,\ G'ovfte VamelL 



IQ'Z THE PATHOLOGY OF THE TEETH. 

and, if it is practicable, a counter opening by trephin- 
ing should be made. In some cases m our practice 
this mode of treatment produced the most satisfactory 
results. If, however, on account of the circumstances 
of the case, the actual cautery cannot be used, a strong 
solution of argeati mtras, applied with pledgets of tow 
or lint, may be substituted. 

" Complications of Operations on the Mouth, — One of 
the most ordinary and serious complications of opera- 
tions on the mouth is the excoriation of the 'bars^ by 
the friction of the speculum oris. The denuded bone 
often exfoliates, rendering the horse uniit for work for 
a month or more. The evil may be avoided by envel- 
oping the transverse bars cf the speculum with tow or 
some other elastic material, and by being expeditious 
in operating. The hemorrhage, which is never abun- 
dant enough to be serious, may be checked by pledgets 
of tow, wet with a solution of either nitric or sulphuric 
acid. 

" Regimen. — The regimen in extreme cases of caries 
has already been indica^d in the account of the case 
of trephining for caries and exostosis of the root of a 
grinder. In addition to well-boiled gruel, mixed or 
unmixed with bran, carrots and similar food will be 
found beneficial."* 

* As horses with defective, diseased, or wom-out teeth require 
soft or jrr'^und food, a few extracts from tlie article on " Food" 
in Prof. Yountt's work entitled "Tlie Horsa" (p. 10-2) and other 
sources will not be out of place here : " Oatmeal gruel consti- 
tutes one of the most important articles of diet for the sick 
horse. Few grooms make good ^rnel. It is either not boiled 
long enough, or a sufficient quantity is not used. The propor- 
tions sbonld be a pound of meal to a gallon of water. It should 
be constantly stirred till it boils, and for five minutes afterward. 
Carrots, according to Stewart's 'Stable Economy,' are a good 



PROF, varnell's views. 163 

Prof. George Varuell, of the Royal Veterinary Col- 
lege of London, the author of a beries of articles ''On 

substitute for grass, and in sick or idle horses render corn un- 
necessary. They improve the state of the skin. At first they 
are slightly diuretic mid luxanve, but the eliecc lessens with use. 
Half a bushel is a large daily allowance. Swedish turnii.s and 
raw potatoes are useful foods. Raw potatoes, sliced and mixed 
with chaff, may be given to advantage, but it is better to boil or 
steam them, as purging rarely ensues. For horses recovering 
from sickness, barley in the form of malt is serviceable as tempt- 
ing the appetite and recruiting the strength. It is best given 
in mashes, water somewhat below the boiling heat being poured 
upon it, and the vessal kept covereil for half an hour. Rye is 
used in Germany, but generally cookad as bread, which is made 
from the whole flour and bran. It is not unusual in traveling 
through some parts of Germany and Holland to see the postil- 
ions help themselves an.l their horses from the same loaf. In 
some nortliern countries peameal is Irequently used, not only as 
food, but as a remedy for diabetes. Linseed, law, ground, or 
boiled, is sometimes given to sick horses. Half a pint may be 
mixed with the feed every night. It is supposed to be useful in 
cases of catarrh. It is very useful for a cough, but it is too 
nutritious for a fever. For a cough it should be boiled and 
given in a brau mash, to which two or three ounciss of coarse 
sugar may be added. Tares, cut after the i)ods are formed, but 
some time before the seeds are ripe, lucern, and sainfoin are 
useful foods. Of the former the variety known as vicia sativa 
is tlie best." 

On page 511 Prof. Youatt says " some greedy horses habitu- 
ally swallow their food without properly grinding it." As a 
remedy he recommends that chaff be mixed with the corn, oats, 
or beans, which, being too hard and sharp to be swallowed uith- 
out chewing, compels the horse to mtisticate his food. He says : 
" Chaff may be com]>osed of e.]ual quantities of clover or meadow 
hay and wheaten, oaten, or barley a^raw, cut in pieces of a quar- 
ter or a half an inch in length, and mixed w^ell together. The 
Allowance of corn, oats, or hean:i is added afterward, and mixed 
with the chaff. 'Many farmers very projierly bruise the oats and 
beans. The whole oat is apt to slip out of the chaff and be lost. 



164 THE PATHOLOGY OF THE TEETH. 

Some of the Diseases Affecting the Facial Reg-ion of 
the Horse's Head" ('•Veterinarian/' 1866-GJ), and 
other productions, has made the disorders of horses' 
teeth a study, and has aided somewhat in clearing the 
'• mystery" that Surgeon Gowing believes will "to a 
certain extent always remain," for he has succeeded in 
casting some light on the etiology of a tooth's greatest 
enemy — caries. His suggestion as to plugging teeth 
with gutta-percha is novel, and in some cases might 
he practicable. However, would not cement, which 
gives such perfect satisfaction in human dentistry, be 
preferable ? It is not expensive, and can be as readily 
introduced into a cavity as gutta-percha; besides, as 
the cavity must first be thoroughly cleaned (no matter 
which is used), its use in the end might save time and 
the tooth be much longer preserved. A horse's tooth 
that can be got at conveniently, ought to be filled as 
easily and, in decay of its neck, perhaps a3 successfully 
as a human tooth. Prof. Varnell's views are in sub- 
stance as follows ("Veterinarian," 1807): 

" Caries of the roots of the grinder teeth is rare and 
generally very difficult to account for. I think that, 
in the majority of cases, it depends upon external yio- 

For old horses, and for those with defective teeth, chaflf is pecu- 
liarly useful, and for both classes the grain should be broken as 
well as the fodder. The proportions are eight pounds of oats 
and two of beans to twentj' of chaflf." 

Concerninor swallowing without grinding Prof. Youatt further 
says: "In cases of this kind the teeth should be examined. 
Some of them may ho unduly lengthened, particularly the first 
of the grinders, or their ragged edges may wound the cheek. In 
the former case the horse cannot properly masticate his food ; 
in the latter he will not, for horses, as too often occurs in sore 
throat, would rather starve than put themselves to much pain.'* 



THE ALVEOLO-DEXTAL PERIOSTEUM. 165 

lence, although we are not always abb to trace it to 
such a cause. lutlammation of the ulveoio-dental peri- 
osteum, especially where it surrounds the root or roots 
of a tooth, would tend to this result. Other causes 
may produce the same effect. Indeed, whenever or 
however effected, when the nutrition of any part of a 
tooth ceases, decay is likely to follow. When caries 
begins from within, it is due to cessation of nutrition, 
arising perhaps from disease of only a part of the cen- 
tral pulp of the tooth. If from without, it arises from 
the periodontal membrane wiiere it meets the gum. 

'' Caries of the cervix (neck) of the tooth is much 
more common than it is in the root ; still it does not 
occur in more than one horse in five hundred. The 
question will naturally be asked, To what does this 
tendency to decay belong ? Under such circumstances 
are we not forced to the conclusion that it must de- 
pend either upon a defective structure of the tooth, or 
that the dentine, enamel, and cement are dispropor- 
tionately developed, or that one of them is defective in 
its parts? Another and perhaps the most frequent 
predisposing cause of caries of tlie neck of the grinder 
teeth is that food becomes impacted between them. 
Its decomposition may not only affect the teeth, but 
the alveolar processes also." 

The professor believes that caries of the crown of a 
tooth is generally caused by the horse biting on a stone 
or piece of metal during mastication. If tlie stone is 
lodged in the cavity of the infundibulum, the pulp of 
the tooth may be injured, for, to use the professor's 
words, '^ the thickness of the tooth between tiie upper 
part of the pulp-cavity and tiie bottom of the deepest 
infundibula is not very great." 



166 THE PATHOLOGY OF THE TEETH. 

Of the treatiTpient of caries of the necks and crowns 
of grinder teetli, the professor tays: 

"x\3 I am not aware of any treatment by which the 
decaying process can be stopped, I would as an experi- 
ment in suitable cases — that is, in those in which the 
diseased part may be got at — plug the tooth with giltta- 
percha, having first thoroughly cleaned the cavity. If 
the plug can be retained in its place, s(3me benefit may 
be derived from its use. Beheving, however, that the 
decomposition of food impacted between the grinder 
teeth is one of the exciting causes of their decay, I 
would advise that it be now and then removed. It 
would not only prevent decay, but in cases where decay 
had already begun, would to some extent check its pro- 
gress. Indeed, I think the health of the horse would 
in many cases be improved by the adoption of such a 
plan." 

While the professor recommends gutta-percha plugs 
for the crowns of slightly decayed grinders, he says 
that, compared with those of the necks, they are "less 
likely to be of even a slight benefit, inasmuch as the 
plug would be removed by attrition." Where the in- 
terior of the grinder is destroyed by disease, and the 
usual longitudinal fracture has occurred, he extracts 
the tooth with the forceps. While, as a rule, the tooth 
fractures longitudinally, the corners, he says, are some- 
times broken off. 

In commenting on the diseases of the alveolar pro- 
cesses, Prof Varnell says: 

"The causes which give rise to this condition of the 
maxillary bones are not easy to define. That a horse 
so affected is from certain peculiarities predisposed to 



DISEASE OF ALVEOLAR PROCESSES. 1G7 

it, there can be no doubt. For exatnpl?, tho teeth be- 
ing plciced at a distance from each otlier, thereby allow- 
ing the food to lodge between them, must be looked 
upon as a predisposing canse. A strumous diathesis, 
which I believe to be more common in the horse than 
is usually supposed, must also be regarded as a predis- 
posing cause. The particles of food which become 
impacted in these unusually wide interdental spaces, 
after a time decompose and give rise to fetid com- 
pounds, which act prejudicially on the parts they are in 
contact with. The membrane which covers the gums, 
and also that which lines the alveoli and is reflected 
on the roots of the teeth, becomes inflamed. The 
inflammation will extend to the bone, the blood-vessels 
of which will become enlarged, as will also the Haver- 
sian canals in which they ramify. The osseous laminte 
surrounding these canals will be partially absorbed, 
and to some extent separated from each other, and the 
enlarged spaces thus produced will be filled with in- 
flammatory exudation. Hence the soft, spongy state 
of the gums and their tendency to bleed from slight 
causes ; hence also the looseness of the teeth in the 
alveoli." 

Of the deformity called Parrof-Moiifli, and irregular- 
ities of the incisor teeth, Prof. Varnell says: 

"This deformity consists in the upper incisor teeth 
projecting in front of and overhanging the lower ones 
to the extent in some instances of an inch and a half. 
The defonnity resembles the upper bill of the parrot, 
which projects over the lower; hence the name. The 
lower incisors, from not being worn off by attrition, 
may become so long that the roof of the mouth is seri- 
ously injured. The deformity is generally associated 



108 THE PATHOLOGY OF THE TEETH. 

with an irregular position of the upper grinders rela- 
tively with the lower. 

''Sometimes the horse, when at pasture, is unable to 
take a sufficient quantity of food to keep himself in 
condition, and consequently he is considered legally 
unsound. But if fed from the manger he experiences 
little trouble in collecting his food; nor will his ability 
to masticate it be interfered with, except perhaps in 
old age. 

" Treatment. — The treatment can only be palliative. 
If the roof of the mouth should become diseased and 
mastication impaired, the only remedy is to reduce the 
length of the lower incisors. The instrument generally 
used is a file or a rasp, but the process is so tedious and 
slow til at it is seldom that much good is done. If the 
sliding-chisel could be brought to bear on them, their 
length could be readily reduced. Talking on the sub- 
ject with my friend, Surgeon Gowing, he suggested a 
modification of this instrument which, I think, would 
answer very well. 

'^ Irregularities of the incisor teeth, both with refer- 
ence to their position and number, are even more com- 
mon than in the grinders, but they seldom cause actual 
disease." 

Prof. William Williams, like Prof. Yarn ell, has per- 
formed his part in elucidating the subject of caries of 
the teeth, and he has also illustrated the transmission 
of vitality to them from the outside — through the me- 
dium of the cement— after it has ceased to flow through 
the pulp on the inside, the pulp having become con- 
verted into dentine. It appears that anything that 
disturbs the equilibrium of this flow of vitality, which 
is the secret of the growth of the teeth throughout 



CEMEXT FILLING THE PULP'S OFFICE. IGO 

life, may causo caries. Prof. Williams says (" Princi- 
ples and Practice of Veterinary Surgery," p. 470) : 

" Caries, dental gangrene, or decay, is almost exclu- 
sively confined to tlie grinder teeth — although I have 
seen the incisors in that condition— and may begin 
primarily in the root, neck, or crown of the tooth. 

'• Caries of the root arises from inflammation of the 
pulp, and may be caused by a constitutional predispo- 
sition or external injury. Inflammation of the pulp, 
however, does not always cause caries. I have several 
cases on record where the roots were enlarged from 
periodontal deposit, with abscesses surrounding the 
roots, without caries. Caries beginning at the roots 
may be due to the obliteration of the pulp-cavity at 
an age when the vitality of the tooth depends upon 
the integrity of the pulp. I need scarcely remind the 
professional reader that the integrity of the teeth de- 
pends upon a due supply, both as to quantity and 
quality, of nutritive materials. 

^'On the roots of a recently cut tooth but little 
cement is met with compared with that which exists 
in old teeth. As age advances the cement increases, 
and the tooth grows from the outside. In man it is 
generally agreed that after a given time the dentine 
ceases to be produced, and that the pulp is converted 
into osteodentine. In the horse the pulp-cavity be- 
comes obliterated gradually by the pulp continuing to 
form dentine, the pulp simply giving way to its own 
])roduct, which ultimately occupies its place and fills 
its cavity. In proportion as the pulp diminishes the 
supply of nutriment is lessened, until at length it is 
entirely cut off* from the interior; to provide for the 
vitality of the tooth the cement increases in quantity 
8 



170 THE PATHOLOGY OF THE TEETH. 

on the root, and at the expense of the perfectly formed 
dentine lying in immediate contact with its inner sur- 
face. That is to say, this layer of dentine is converted 
into cement by the dentinal lacnnge undergoing dila- 
tation and becoming identical with the hollow spaces 
or cells of the cement. The tooth now draws its nour- 
ishment from the blood-vessels of the socket, and thus 
continues, long after the obliteration of its pulp-cavity, 
to perform its part in the living organism. 

"This is the natural condition of old teeth. But 
when the pulp-cavity is obliterated at an early age, by 
a too rapid formation of dentine, and consequent ob- 
literation of the pulp when the cement is not yet sufifi- 
ciently developed to supply nourishment to the whole 
tooth, caries must be the result. Many cases of caries 
that have come under my observation have resulted 
from this cause, and very often the disease is confined 
to that part of the cement that dips with the enamel 
into the interior of the tooth, splitting it into several 
longitudinal fragments. 

"Caries of the neck of the tooth is seen in those 
horses whose teeth are wide apart, and is caused by 
the food remaining in the interspaces, and by decom- 
position exciting inflammation in the periodontal 
membrane. Caries of the neck is very commonly met 
with in the teeth of dogs, sometimes causing abscesses 
in the cheek. 

"Caries beginning at the crown is due to a portion 
of the dentine losing vitality and the power of resist- 
ing the chemical action of the fluids of the mouth. A 
portion of the enamel of the crown may be fractured 
by biting a stone or piece of metal contained in the 
food. Mere fracture of the enamel, however, is insuffi- 
cient of itself to lead to caries of the teeth in the lower 



SIFTIXG THE FEED. 171 

animals, for it is a substance that is gradually worn 
off by mastication; but the violence whicli has caused 
fracture of the enamel, may at the same time have 
caused such an amount of injury to the dentine that 
it dies, and progressively becomes decomposed. In 
man it seems there should be death of the dentine and 
acidity of the oral fluids before caries can take place, 
test-paper ai){)lied to a carious tooth invariably show- 
ing the presence of free acid, and a very smaft perfora- 
tion in the enamel may coexist with a considerable 
amount of disease in the dentine." 

Surgeon T. W. G owing, of London, a well-known 
inventor of dental instruments (veterinary), in an 
" Essay on the Diseases of the Teeth of the Horse," 
which was printed in ''The Veterinarian" for 1851 
(p. 632), in substance says: 

"I am aware that the cause of disease of the teetli 
must to a certain extent always remain a mystery; yet 
from observation and reflection we may be able to de- 
duce conclusions which practice will confirm. 

" Let us consider the two classes of horses that we 
are principally called upon to attend, namely, the cart 
or draft-horse, and the hack or carriage-horse. So far 
as my observations have led me, the latter class are 
less liable to diseases of the teeth than those of a 
coarser breed. Now, may not this be caused by the 
better care they receive in the stable? The good and 
efficient groom regularly sifts the provender previous 
to feeding his horses, and thus rids it of stones, glass, 
&c. The cart-horse and the machine-horse of our 
London omnibus proprietors, not receiving this atten- 
tion, are mt)re subject to diseases of the teeth. Be- 
sides, it is a common practice with carters to sprinkle 



172 THE PATHOLOGY OF THE TEETH. 

the provender with siilpliuric acid, and we well know 
how acids affect the teeth. If such practices be al- 
lowed, diseases of the teeth may be readily accounted 
for. 

"The teetli being lowly organized, soon lose their 
power of self-preservation. Tney are affected by the 
general health of the animal. Should the function of 
the stomach or alimentary track be deranged, the teeth 
— from the general health of the animal being inter- 
fered with, and from the local functional derangement 
— of all parts of the bod}^ are the first to suffer or de- 
cay. Absorption of the gums, which may be caused 
by the decayed food that lodges between the grinders, 
is often followed by decay of the cement, which, beiug 
the most exterior as well as the most highly organized 
of the three substances composing the teeth, is the 
first to yield." 

After describing the usual symptoms of diseased 
teeth. Surgeon Gowing asks : 

" Who that has observed these symptoms, can hesi- 
tate for a moment to acknowledge that the animal is 
suffering pain, which, if we were to say arose from 
toothache, would not be beheved by our employers?'' 

Prof. W. Youatt says in substance ("The Horse/' 
p. 230) : 

" Of the diseases of the teeth we know little. Cari- 
ous teeth are occasionally seen. They not only render 
mastication difficult, but they sometimes impart a fetid 
odor to the food, and the horse acquires a distaste for 
aliment altogether. Carious teeth should be extracted 
as soon as their real state is known, for the disease is 
often communicated to the contiguous teeth and to 



FUXGUS H^MATODES. 173 

the jaw also. Dreadful cases of ^fungus haematodes' 
have arisen from the irritation of caries. 

"Every horse tliat gets thin or out of condition, 
without fever or other apparent cause, should have his 
teeth and mouth examined, especially if, without any 
indication of sore throat, he 'quids' his food; or if he 
holds his head to one side while he eats, in order to 
get the food between the outer edges of his teeth. The 
cause is irregular teeth. Such a horse is materially 
lessened in value and is to all intents and purposes 
unsound, for although the teeth may be carefully sawn 
down, they will project again at no great length of 
time. A horse cannot he in full possession of his nat- 
ural powers without perfect nutrition, and nutrition 
is rendered imperfect by any defect in mastication." 

Prof. R. Owen, in his work entitled "A History of 
British Fossil Mammals and Birds " (pp. 388-9), gives 
an account of a diseased fossil horse's tooth which he 
found at Cromer. He says he is " induced to cite one 
of the curious examples of disease in an extinct animal 
from the rarity of its occurrence in the tissue which is 
the subject of it." The facts of this rare case are as 
follows: 

" One of the Cromer fossil teeth, from the lower jaw, 
with a grinding surface measuring one inch five lines 
in long (antero-posterior) diameter, and eight lines in 
short (transverse) diameter, presented a swelling of 
one lobe, near the base of the implanted part of the 
tooth. To ascertain the nature and cause of this en- 
largement, I divided it transversely, and exposed a 
nearly spherical cavity, large enough to contain a 
pistol-ball, with a smooth inner surface. The parietes 
of this cavity, composed of dentine and enamel of the 



174 THE PATHOLOGY OF THE TEETH. 

natural structure, were froni one to two lines and a 
half thick, and were entire and imperforate. The 
water percolating the stratum in which this tooth 
had lain, had found access to the cavity through the 
porous texture of its walls, and had deposited on its 
interior a thin ferruginous crust; but the cavity had 
evidently been the result of some inflammatory and 
ulcerative process in the original formative pulp of 
the tooth, very analogous to the disease called 'spina 
ventosa' in bone." 



CHAPTER IX. 

THE DENTISTRY OF THE TEETH. 

Reports of Cases Treated by Various Surgeons. — Gutta-Pcrcha 
as a Filling for Trephined Sinuses. — Teeth Pressing? ugainst 
the Pahxte. — Passing- a Probe through a Decayed Tooth. — 
Death of a Horse from Swallowing a Diseased Tootli. 

Horsemen, farmers, and other practical men will 
find much useful information in the present chapter, 
for it is based on the experiences of Veterinary Sur- 
geons, whose reports appear in the various volumes of 
"The Veterinarian" (printed monthly in London), 
and to which I am so much indebted for other useful 
information. It is probably not too much to say that 
the more generally the chapter is read the fewer horses 
will be killed in the future for having decayed teeth, 
accompanied with a discharge from the nostril. 

In "The Veterinarian" for 1856 (p. 437) Surgeon J. 
Horsburgh reports the following interesting case, en- 
titled "Chronic Nasal Gleet produced by a Diseased 
Tooth:" 

"About twelve months ago I was consulted about 
the case of a mare with a discharge from the near nos- 
tril. She had been under treatment for eighteen 
months, and the superior maxillary sinus had been 
opened with* the trephine. The discharge, however, 
continued to flow, both from the nostril and the 



176 THE DENTISTRY OF THE TEETH. 

wound, notwithstanding the trephining had been per- 
formed a year before I saw the animal 

" The deflnotion had an offensive smell, and the sub- 
maxillary gland was enlarged, causing suspicion of 
glanders. The opening had been made a little too 
high, so that the central instead of the superior j)art 
of the sinus was perforated. I found that the whole 
mischief was caused by a diseased tooth. With the 
assistance of a smith I removed the tooth, which was 
split up its middle and considerably decayed. It was 
more than two inches long, and was bent forward to- 
ward the cheek. The odor was most offensive. I then 
opened the frontal and maxillary sinuses, both of 
which were filled with fetid pus. The wounds were 
first treated with a weak solution of chloride of lime, 
and subsequently with an ordinary astringent lotion. 
In addition to the local treatment, I administered the 
din iodide of copper. 

"After a considerable time the wounds were allowed 
to heal, and the mare appeared much better. But very 
shortly the discharge began to flow again worse than 
ever, and the smell was almost intolerable. Deter- 
mined, if possible, to make a cure of the case, I cut 
into the sinus again with the skull-saw, taking out a 
triangular piece of bone about two inches long by one 
inch and a half broad. At the upper part of the 
ca^dty I found some masticated food in a state of de- 
composition. It had passed through the alveolus into 
the sinus. Fractured bones were removed, and the 
opening being extended through into the nostril, a 
small instrument could be passed down it into the 
mouth. A weak nitric acid lotion was used to induce 
fresh inflammatory action, and, if possible, to fill up, 
by an effusion of lympii, the passage through which 



CURED INSTEAD OF KILLED. 1T7 

the food was pressed upward from the mouth into the 
cavity. The external wound was dressed with an 
ordinary heahng lotion, and tow was put into it daily, 
and pressed downward to the mouth. A little bUster 
liniment was also occasionally apphed. 

'• Before operating, the frontal sinus on the affected 
side was considerably more bulging than the other. It 
is now reduced, and the wound has healed. The dis- 
charge from the nose has stopped, and there is no 
smell. Thus, after about two years and a half of 
treatment, this mare, now only five years old, is able 
to resume her work, and has every appearance of being 
likely to remain well. 

"Had I not been able to effect a cure by the closing 
of the passage into the mouth, I would have tried 
filling it with gutta-percha. If a discharge were to 
take place again in this case, it would no doubt depend 
on the existence of a small aperture, and, under such 
circumstances, I should not hesitate to again cut into 
the sinus and endeavor to close the opening in the 
bone with gutta-percha, or some similar substance." 

Surgeon H. Surmon, in an article " On the Extrac- 
tion of Projecting Teeth," tells how he saved a horse 
that had been ordered killed by its owner ("Veterina- 
rian," vol. ii, p. '^5): 

"Last year a neighbor of mine had a horse which 
had been losing flesh for some time, and his appetite 
was gradually diminishing. When I first examined 
the horse I saw no appearance of disease that could 
affect his appetite, and looking at his mouth I per- 
ceived no laceration of the cheeks or other injury. 
The horse-grew worse, became almost a skeleton, and 
its owner ordered that it be killed. Being informed 



178 THE DENTISTRY OF THE TEETH. 

of the fact, I expressed a wish to examine his mouth 
once more. I accordingly put a balling-iron into his 
mouth and introduced my hand, and at the extremity 
of the grinders I found two teeth, one on each side of 
the lower jaw, which had grown long enough to press 
into the roof of the mouth, and thus prevented the 
animal from eating. I endeavored to extract these 
teeth with an instrument similar to that used for the 
human teeth, but without effect, as it could not be 
got on them. I then contrived an instrument which 
was very simple. When it was passed up the mouth, 
the tooth became fixed between the divided end of the 
iron; the handle being then turned, the tooth was 
extracted with the greatest ease. From that moment 
the horse began to feed, and rapidly improved in con- 
dition. In a short time he went to work, and has done 
well." 

Surgeon C. May, of Maiden, Eng., thus tells how he 
cured "A Case of Disease of the Jaw" (" Veterinarian," 
1834, p. 93); 

" I was requested by Mr. Earn, of Purleigh, to look 
at a horse which he told me had a 'cancer' in his jaw. 
I found my patient, a fine young chaise-horse, looking 
very poor, and having a constant discharge from the 
region of the root of the second lower grinder. There 
was considerable enlargement of the bone, which led 
me to suspect disease of the tooth, and which, on ex- 
amination, proved to be true. On introducing a probe 
into the orifice, I found that it went through the tooth 
into the mouth. I was informed that this sujiposed 
cancer had been under the treatment of a farrier, and 
that the poor beast had been subjected to many pain- 
ful caustic applications. As I was satisfied that no 



THREE Ul'PEK GRINDERS EXTRACTED. 179 

good could be done to tlie jiiw as long as the tooth re- 
mained in it, I decided to extract it. I had an instru- 
ment made similar to the key used in human dentistry, 
witli a handle like that of an auger. Having cast my 
patient and lanced the gum, I fixed the instrument on 
the tooth and succeeded in extracting it, although it 
required nearly all my strength. There was but 
trifling hemorrhage, and the 'cancer' soon got well. 
I think our patients are more frequently the subjects 
ol: toothache than we suppose. Perhaps ^quidding' in 
many of them might be traced to a carious tooth." 

In a report of ten cases of diseased teeth that were 
treated at the Edinburgh Veterinary College during 
the year 1845, the details of one is thus given in ''The 
Veterinarian" (1845, p. G2G): 

"A cart-horse was brought here with a profuse flow 
of white, clotty, and offensively smelling matter from 
the off nostril. The external plate of the superior 
maxillary bone on the same side was considerably 
elevated, and pain was evinced on pressing the part. 
There was no ulceration visible of the Schneiderian 
membrane, but the submaxillary lymphatic glands 
were somewhat enlarged. On examination there ap- 
peared to be disease of the superior maxilla, in which 
the grinder teeth were involved. Considering the 
extent to which the facial bones were afi'ected, it was 
decided, as the only way of efiecting a permanent cure, 
to extract the diseased teeth. The horse was cast, and 
by means of the ordinary tooth-key three of the upper 
back teeth were extracted. In a few days after the 
operation the discharge diminished in quantity, and 
under the continued appHcation of proper remedies it 
entirely subsided, and the horse is now well. 



180 THE DENTISTEY OF THE TEETH. 

"There are in this, as in former reports, cases where 
the superior maxillary bone and its sinuses have been 
injured from the elongation of the grinders of the in- 
ferior maxilla, causing a nasal discharge in many cases 
mistaken for that of glanders. They are easily reme- 
died by shortening the teeth with the cutting-forceps." 

Surgeon A. II. Santy says ("Veterinarian," 1875, 
p. 835): 

"On the 26th of June I bought a six-year-old mare. 
She continued to work till July 17th, when she was 
suddenly taken with a slight running from the near 
nostril, which greatly increased in twenty-four hours. 
The submaxillary gland on that side swelled. There 
was slight tenderness of the throat and loss of appe- 
tite, which soon passed away. I showed the animal to 
a brother surgeon, and told him I thought of trephin- 
ing. He said: 'Don't be in a hurry.' It struck me 
there might be something wrong with the grinders. I 
examined them, and found the fourth superior near 
side tooth with a depression on the outside and slightly 
raised from the surface of the other teeth. There was 
slight fetor from the food lodging there. I at once 
cast the mare, and with some difficulty extracted the 
tooth. I then dressed the wound and nursed the mare 
for a few days. The discharge from the nostril ceased 
in ten days. I have the mare now in constant work." 

The above case deserves consideration for several 
reasons. Thousands of horses with precisely the same 
symptoms have been killed because the surgeon could 
not discriminate between diseased teeth and glanders. 
The "slight tenderness of the throat and loss of appe- 
tite, which soon passed away," was the result of the pus 



"DONT BE IN A HURRY." 181 

finding an outlet, winch gave partial relief. Surgeon 
Santy acted on the advice, " Don't be in a hurry," and 
consequently had time to think. The depression on 
the outside of the tooth and its sUght projection above 
the common level, were signs that the trained eye only 
will detect. However, had the operation been delayed 
for a short time, in addition to the depression on the 
outside of the tooth, the gum would have been more 
or less shrunken, and the tootli, as a natural conse- 
quence, would have appeared longer.* Further, in- 
stead of the tooth being "slightly raised from the sur- 
face," it might have been below it; for, the inflamma- 
tion having subsided, and the root-s being shortened 
by the caries, it is liable to be forced deeper into the 
socket. Its next natural movement, the caries having 
destroyed its periosteum, is to drop out altogether. 

As an offset to the foregoing cures, a few cases that 
terminated in death will be given. Surgeon Samuel 
Baker, in a letter to the editor of " The Veterinarian " 
(1845, p. 216), says: 

" I was called in by a neighboring farmer to examine 
a two-year-old colt, which had to all appearance a poly- 
pus as large as a cricket-ball grooving out of the right 
nostril. Respiration through that nostril was stopped. 
In order to ascertain its nature, I had the colt cast, 
and found that the nostril was filled with a hard fleshy 
tumor, which distended the other nostril also. After 
making an incision through the ala and side of the 
nostril, I removed a portion of the tumor, over a pound 
in weight. But, as still no air passed through, and 

* Shrinkajre of tlie o^nra, accordint^ to C. D. House, invariably 
follows caries of the roots of the teeth. 



182 THE DEKTISTKY OF THE TEETH. 

there seemed not the slightest chance of gaining a 
passage, I ordered the colt to be killed. 

''In dissecting the head I found that the cause pro- 
ceeded from a decayed tooth, at the root of which was 
a bag of matter about the size of a walnut, which by 
no possible means could relieve itself." 

Surgeon Baker does not say which of the six teeth 
(of course it was an upper grinder of the right side) 
was diseased. The complications of the caseappear to 
have been unusual, otherwise the bag of matter would 
have sooner or later found an outlet through the nos- 
tril. The extraction of the tooth would have probably 
afforded an outlet through the alveolus; this failing, 
the effect of trephining the sinuses should have been 
tried. 

Surgeon William Smith, of Norwich, Eng., reports 
a case of caries of the roots of several grinder teeth, 
accompanied by a discharge from the nostril, which 
he admits he mistook for ozena. He says ('^ Veterina- 
rian,'^ 1850, pp. 381-2) : 

^*I was requested a few days ago to visit a horse 
which was supposed to be 'glandered.' I found the 
animal in a most emaciated and pitiable condition, 
with a copious greenish and very offensive discharge 
frojn the left nostril, with slight tumefaction of the 
gland on the same side. There was no appearance of 
ulceration, but the Schneiderian membrane had a 
leaden, dirty hue. Taking all the circumstances into 
consideration, I ordered the animal's destruction, but 
had its head sent to my infirmary. 

" Meeting Surgeon Gloag, of the Eleventh Hussars, 
I told him I thought I had a case of ozena. He ex- 



OXE TOOTH L03T AXD FOUR DISEASED. 183 

pressed a wish to be present at the examint^tion of the 
head, and I was glad to avail myself of his assistance. 

"A longitudinal cut was made on each side of the 
septuhi nasi, and a transverse anc at a line between 
the. center of the orbits. Another longitudinal cut, 
dividing the maxillary sinuses, was made just above 
the roots of the grinder teeth on each side. By this 
means we had an opportunity of examining the sep- 
tum nasi on each side ; also the turbinated bones, and 
the frontal and maxillary sinuses. 

"On the left side we found an accumulation of pul- 
taceous food, covered with thick pus, completely filling 
the maxillary sinus, and extending to the turbinated 
bones. The frontal sinus contained an accumulation 
of inspissated (thickened) pus, the septum nasi was of 
a leaden hue, as also the membrane covering the tur- 
binated bones, which was much inflamed and thick-* 
ened, but there was no appearance of ulceration. 

" The difficulty was to ascertain how the food got 
there. After careful search, it was very evident that 
it could not have passed through the nostril. "We 
therefore gradually dislodged the food and matter, 
searcliing for the former's entrance, and at last found 
a hole in the alveolar space belonging to the last 
grinder, the root of Avhich was completely gone, only 
a small portion of the crown itself remaining. The 
hole w^as sufficiently large to admit the little finger. 
The mystery was solved— the process of mastication 
had deposited the food in the sinus. The fourth 
grinder was absent, ha\4ng been lost evidently from 
previous disease. 

"On examining the right side of the bond we found 
the turbinatM bones and meml)ranes covering tlie 
septum nasi comparatively healthy, but we discovered 



184 THE DENTISTRY OF THE TEETH. 

a cyst, al)oiifc the size of a walnut, iii the maxillary 
sinus. It contained limpid fluid, and occupied the 
space immediately over the root of the fourth grinder 
tooth, which was decayed and quite loose, and bcloiu* 
the level of the other teeth. The teeth of the lower 
jaw appeared healthy." 

Without further examination, Surgeon Smith sent 
the head to the editor of " The Veterinarian," who 

says: 

"The mare (that being the sex according to the 
teeth) we should take to have been about twenty years 
old. Her incisors are sound, and so are the grinders 
of the lower jaw. But in the near (left) upper jaw, 
the second, fourth, and sixth teeth are in a state of 
progressive decay, and the same is true of the fourth 
k>oth of the off side. The vacuity caused by the de- 
fective last grinder has opened a passage to the an- 
trum, through which the food has passed, and thence 
into the near chamber of the nose, between the tur- 
binated bones, where it was discharged through the 
nostril. This accounts for the irritation on this side 
of the head, for the suppurated and even ulcerated 
condition of the Schneiderian membrane, and for the 
suspicious discharges. It was evident enough that 
there was no glanders. The very circumstance of ali- 
mentary matter being discharged through the nostril 
was enough to prove the contrary." 

Still another case of destroying a horse for what 
merely appeared to be glanders is recorded by Prof. 

* The italics are mine. Compare with comments on Surgeon 
Santy's case, page 181. 



A GOYERNMEXT HORSE'S HARD LOT. 185 

William Percivall in liis work entitled "Hippopath- 
ology" (vol. iij p. 237). He says: 

"There are instances on record of carious teeth be- 
ing productive of such evil consequences as to lead, 
through error, to a fatal termination. The following 
relation ought to operate on our minds as a warning 
in jironouncing judgment in cases of glanders, or at 
least in such as assume the semblance of glanders : 

'^A horse, the property of government, became a 
patient of Surgeon Cherry on account of a copious 
defluction of discolored and purulent matter from the 
near nostril, unaccompanied by submaxillary tumeftic- 
tion, or by ulceration of the Schneiderian membrane. 
For two or three months the case was treated for 
glanders; but no improvement following, a consulta- 
tion was deemed necessary, the result of which was 
the horse was shot. 

^'On examination of the head, the third upper left 
grinder proved to be carious, one-third of its root be- 
ing already consumed and the remainder rotten. The 
formation of an abscess within its socket had loosened 
the tooth, and the matter flowing therefrom had estab- 
lished a passage into the contiguous chamber of the 
nose. The antrum was also in part obstructed by the 
deposition of osseous matter. 

"This is a case which, but for the inquisitiveness of 
Surgeon Cherry, would have merged into that hetero- 
geneous class of diseases passing under the appellation 
of chronic glanders. 

"My father's museum contained several specimens 
of carious teeth. One was that of a grinder, the inte- 
rior of whicl\ was black and rugged, from being eroded 
by ulceration, and the roots had from the same cause 



186 THE DENTISTRY OF THE TEETH. 

mouldered awaj. Two others presented brittle exos- 
toses u23on their sides, forming spacious cavities within 
and communicating with the contiguous teeth. One 
of them exhibited a perforation through which pus 
appeared to have issued. Both seemed to have been 
cases which had origiuated in internal injury." 

Prof. George Varnell closes his series of papers " On 
Some of the Diseases Affecting the Facial Region of 
the Horse's Head" ("Veterinarian," 1867), by giving 
an account of a case of *osteo-sarcoma,' the disease, in 
his opinion, being caused by carious teeth. The case 
illustrates the importance of veterinary dentistry ad- 
mirably. He says: 

"Further to illustrate varieties of the diseases of 
the sinuses, I will relate.a case of osteo-sarcoma which 
came under my care in Jul}^ 18G2. I found the horse 
had an offensive discharge from tlie left nostril. The 
face below the orbit was enlarged, and the eye slightly 
displaced in its cavity. I also found that the three 
last grinder teeth in the upper jaw of the affected side 
WT,re quite loose in their sockets, from which a dis- 
charge of a highly fetid character issued. Percussion 
on the side of the face indicated extensive disease, and 
the enlargement readily yielded to pressure. As there 
was not the slightest prospect of a cure, I suggested 
that the animal be killed. 

'^Post-morterii Examination. — The outer walls of the 
sinuses, which were very thin, were first removed, dis- 
closing a mass of disease the seat of which was oppo- 
site the roots of the fourth grinder tooth, which was 
carious. This abnormal growth occupied the maxil- 
lary, malar, lachrymal, and a portion of the frontal 
sinuses, and had also encroached upon the orbit to 



SWALLOWIN^G A DISEASED TOOTH. 187 

such an extent as to displace the e3'e'oall. The outer 
surface of the diseased mass was soft in texture. It 
had a gelatinous appearance, and when pressed w^ith 
the blade of the scalpel, a thin, watery fluid oozed from 
its surface. A SL'Ction of it i)resented a grayish-red 
appearance, with lightish streaks of iioro-osseoas mat- 
ter diverging from its roots and extending irregularly 
through its entire substance. The facial bones them- 
selves, in the region of the disease, had in some parts 
disappeared altogether, while in others the cancelli 
were much enlarged, their osseous partitions partially 
absorbed, and their interstices filled with a deposition 
of a fibro-cellular strncture. 

" Such is a brief outline of this malignant and in- 
curable disease, which I have no doubt primarily arose 
from caries of the roots of the grinder teeth." 

Prof. Renault, of Alfort, France, is the author of an 
interesting account of a very unusual case, namely, 
the swallowing of a diseased tooth by a horse, which 
appeared originally in the '* Recueil de Medicine Vete- 
rinaire'' for 1830. It is an argument against casting 
horses for the purpose of extracting their teeth, for 
had the horse been in a standing position the accident 
would not have occurred. When a horse's head rests 
upon ^he occiput, the muzzle pointing upward, it is as 
natural — the tooth being free of the forceps as well as 
the socket — for it to drop into the throat as it is for 
water to run down hill. The full history of the case 
is as follows : 

" A post-horse, seven years old, had not fed well, and 
had been losing flesh during about three weeks. On 
the 2Gth of November, 1835, I saw him for the first 
time. Tlie postilion told me that within the last two 



188 THE DENTISTRY OF THE TEETH. 

days he had eaten with more difficulty and pain than 
before, and dropped ahnost the whole of the hay and 
corn from his month before it was perfectly masticated. 
Hs had also observed that during the mastication of 
his food the horse always inclined his head to the left 
side. 

" On examining the mouth, I easily recognized the 
cause of this difficulty of mastication. The gum, at 
the second grinder of the right lower jaw, was swollen 
and ulcerated, both within and without. The least 
pressure on the gum at this spot inflicted great pain, 
and the animal also suffered when tlie crown of the 
tooth was touched. On that portion of the jawbone 
contiguous to the diseased tooth, was a considerable 
swelling, hot and painful, which the postilion told me 
had existed for about twelve days. It was increasing in 
size every day. The breath was only slightly fetid, 
and there was nothing to indicate caries of the tooth. 
I expressed the opinion that the caries, if it existed, was 
confined chiefly to the root of the tooth, and that the 
ulceration of the alveolar septa beneath, of wdiich there 
was no doubt, rendered its extraction necessary. 

" On the following day the horse was cast, and his 
mouth being kept open by the proper instrument, the 
key was applied to the tooth. It resisted my first 
effort to draw it, but, on the second trial, gave way 
with a peculiar sound, which made me suspect that it 
was broken. The instrument (gag) was then taken 
out of the mouth, in order that the tooth might 
escape, but, to my great surprise, no tooth could be 
seen, notwithstanding I carefully searched for it. It 
was now plain that the tooth had been swallowed. I 
then assured myself that the tooth had been entirely 
extracted, and as, during the operation, the fr^enulum 



OPENING THE JUGULAR. 189 

of the tongue had been wounded, I deferred tlie cau- 
terization of the alveolus till the following day. 

*-As to the swallowing of the tooth, I gave myself 
very little concern. I did not think that so small a 
body was likely to form any serious obstruction in the 
intestinid canal, or that its temporary sojourn in the 
large intestine could become at all dangerous; so I 
merely directed that the mouth be frequently washed 
with warm water, and forbade the use of hard food. 

"29th. I again saw the horse, and no serious con- 
sequence had yet followed the operation. He ate bar- 
leymeal mash with appetite, and a small quantity of 
hay. Two hours afterward he was brought to the 
School. He was very uneasy, and his belly was enor- 
mously distended, the swelling being principally on 
the right side, where the resonance was considerable 
on percussion. The horse was continually endeavor- 
ing to expel something from the anus, and the strain- 
ing was so great that I feared the rectum would pro- 
trude. The efforts were follovred by small mucous 
dejections, mixed with portions of food. The mucous 
membrane was of a subdued red color. These symp- 
toms had been preceded by swelling at the flanks; 
colicky pains had followed, but they had ceased, 
and nothing now remained except the enlargement of 
the belly and the incessant effort to expel the freces. 
The artery was full, but the pulse was almost imper- 
ceptible; the extremities were cold and the mucous 
membranes of a red violet color. The nostrils were 
convulsively dilated, respiration difficult and acceler- 
ated, and the walk staggering; the skin was covered 
with sweat, and, in a word, the animal presented every 
symptom of immediate suffocation. On this account I 
immediately opened the jugular and abstracted about 



190 THE DENTISTRY OF THE TEETH. 

twelve pounds of blood. The patient was very con- 
siderably relieved. I then ordered all four legs to be 
well rubbed with essential oil of turpentine. 

"There now appeared to me a connection between 
these symptoms and the swallowing of the tooth. But 
where was this tooth ? Entangled in the pyloric ori- 
fice of the stomach ? I could not perceive any symp- 
tom of gastric disease. Was it in the convolutions or 
the ca3cal portions of the small intestines? How then 
could I explain the distention of the large intestines 
and the expulsive efforts, so violent and continued? 
It was more likely that the tooth was lodged either in 
the colon or the caecum, or in the irregularities of the 
floating colon, and partially or entirely prevented the 
passage of the faeces. It was hard to believe that in 
the lapse of two days the tooth could have reached the 
further part of the intestines. 

" Having determined on the nature of the disease, I 
was somewhat embarrassed to ascertain its precise seat. 
I attempted to introduce my hand into the rectum, 
but the circumvolutions of the bowels w^re so much 
distended with gas, and so completely fiilled the pelvis, 
and the mere introduction of my finger caused such 
violent efforts to expel the contents of the rectum, that 
I was forced to desist. 

" In the meantime the swelling rapidly increased, 
and again threatened suffocation. I then determined 
to use the only means in my power to prevent this, 
namely, to puncture the caecum. This was effected 
with the trocar used for hoove in sheep, and in an in- 
stant the swelling subsided, and the symptoms of suf- 
focation disappeared. I was then enabled to introduce 
my hand into the rectum, but I could not discover the 
situation of the tooth. While exploring the rectum, 



THE TOOTPI IX THE C^CUM. IGl 

however, the 'canula' escaped from the caecum. The 
swelling now began again, and increased with extraor- 
dinary rapidity. I was about to plunge the trocar into 
the intestines once more, when I perceived that all 
treatment was useless. The animal was ia the agonies 
of death, and in a few moments it expired. 

"The post-mortem examination took place immedi- 
ately after death. I found in tl>e heart and lungs all 
the lesions which usually accompany death by suffoca- 
tion. The digestive canal was distended by gas. The 
stomach was half filled with barleymeal, but not a par- 
ticle of it was found throughout the whole extent of 
the small intestines, nor was there the slightest trace 
of inflammation of the mucous coat. The caecum con- 
tained a great quantity of blood- tinted fluid, but there 
was no lesion or redness on any part of its internal 
face to indicate the source of the blood. Probably it 
came from the wound made by the trocar. 

" In the cavity of the caecum, toward its point, we 
found the tooth ; but, I repeat it, there was no inflam- 
mation of its mucous membrane. There was, how- 
ever, a slight discoloration of the membrane toward 
the end of the colon ; it was of a slate color, and was 
probably caused by the sulphuretted hydrogeti gas. 

"Are we to conclude that the death of the horse 
was caused by the tooth? However extraordinary 
such a conclusion may at first appear, I am very much 
inclined to believe that it affords the best explanation 
of the mystery. The horse had scarcely eaten for 
fifteen days. Tliis long fast had produced a compara- 
tively empty condition of the digestive canal and an 
augmentation of its irritability up to the moment of 
the operation. The quietness of the horse and his 
appetite and apparent health during the two days pre- 



102 THE DENTISTIIY OF THE TEETH. 

ceding his death, proved that the tooth passed without 
obstacle through the first part of the intestinal canal. 
Having arrived at the caecum, however, which was 
almost empty, and lying for a greater or less time at 
the inferior part of its mucous coat, its hard and irreg- 
ular surface produced irritation ; and as the contrac- 
tions of this intestine were not effectual to seize the 
tooth and return it to the beginning of the colon, the 
prolongation of the irritation might suspend the diges- 
tive function of this viscus, augment its secretions, 
and cause the continaal effort to expel the faeces. 
Hence also arose the gaseous distention of the abdo- 
men. As to the death of the horse, the tooth was only 
the indirect cause. The direct cause was suffocation, 
which was produced by the distention of the bowels." 

Prof. Bouley and Surgeon Ferguson report two 
fatal cases of swallowing teeth that came under their 
own observation. " In the first," they say, '^ the horse 
succumbed in a tympanitic affection, accompanied by 
extreme pain, and death was produced by asphyxia." 
The second case, judging by the short description of 
it in '-The Veterinarian" for 1844, is the identical 
case just described by Prof. Bouley's fellow-townsman, 
Prof. Renault. Messrs. Bouley and Perguson further 
say: 

*^Such, however, is happily not always the result of 
swallowing a tooth or the fragment of a tooth ; but 
even the possibility of such a result ought to make 
the surgeon cautious. Moreover, the swallowing of a 
tooth may cause serious consequences at some future 
time. We refer to the formation of those productions 
called intestinal calculi.' The tooth, on account of 
its being indige.itiblo, acts as the nucleus for the future 



SWALLOWING A SOUXD TOOTH. 193 

calculus, as indeed may any similar body, which fact 
has been demonstrated by Prof. Morton, of the Lojidon 
Veterinary Collei^e, in an excellent paper on 'The For- 
mation of Calculus Concretions in the Horse.'"* 

Surgeon W. A. Cartwnght reports that he extracted 
three grinders from a 'quidding' mare, one of which 
she swallowed ("Veterinarian," vol. iii, second series, 
p. 277). The tooth was sound, which may account for 
the favorable result of the case. 

* TJie Enterprise, published in Virginia, Nevada, in its issue 
for December 12, 1878, contains an article entitled " A Stone 
found in a Horse's Jaw," which is in substance as follows : " For 
a lonj? time a lump has been noticed in the side of the jaw of a 
horse belono;ing to Superintendent Osbiston, of the Gould and 
Carry and Best and Belcher mines. It was near the jawbone, 
and no liniment had power to soften or drive it away. Yester- 
day a veterinary surgeon made an incision, and to his astonish- 
ment removed a stone about two inches long and one inch in 
diameter. It is yellowish-white in color, and apparently as hard 
as marble. Mr. M. M. Frederick, the jeweler, divided it longi- 
tudinally, and in its center was what appeared to be a petrified 
grain of barley, which was also divided longitudinally. Around 
tiiis nucleus the stone had formed in regular layers, the rings of 
■which could be distinctly traced. The material of which the 
stone was composed appeared to be the same as that of the in- 
cnistations on the tubes of boilers. It is conjectured that the 
grain of barley pierced the gum and imbedded itself in the flesh, 
and that the saliva, flowing in, deposited limy matter similar to 
that which is sometimes found on the teeth of horses as well as 
men. A small concretion having thus been formed, it gradually 
grew, the channel by which the grain of barley entered no doubt 
remaining open and allowing an inflow of saliva." 

Tiie above case is another proof that Dr. Dunglison was right 
when he said that calculi " may form in every part of the animal 
body." 



CHAPTER X. 



FKACTURED JAWS 



How Caused, and how to Distinguish an Abrasion of the Gums 
from a Fracture of the Bone. — Replacing an Eye, Amputa- 
ting part of a Lower Jaw, taking a Fractured Tooth and 
Bones out through the Nostril, &c. 

Fkactures of the jaws of the horse are of common 
occurrence. They may exist independently, but they 
are often complicated with and the cause of diseases of 
the teeth. Caries of the jawbone proper, and even 
some of the facial bones, is often communicated to the 
alveoli, and when necrosis ensues the destruction of 
the teeth is inevitable. This is as true in the case of 
the horse as in tha-t of man. 

The rami (branches) of the lower jaw are common 
seats of fracture, a frequent cause of which is the use 
of sharp curved bits; but rough usage by the rider or 
driver will now and then cause fractures even with a 
smooth bit. As a rule, at first, the gums only are 
affected; but in a short time the periosteum and bone 
are reached. Prof. Varnell says: "If the matter that 
escapes be of a grayish-brown color and fetid, it will 
indicate disease of the bone ; but if it is from a sub- 
cutaneous abscess, the discharge will be simply of a 
purulent nature, and a speedy cure may be effected by 
the application of very r-in-.ple remedies." 



SURGEON FLEMING'S DISCOVERY. 195 

When a fracture has been proclnced, inflammation 
and fetor will follow, and the horse loses his appetite. 
If the bone is removed and the horse is allowed to rest 
for a few days, tne wound "will heal; otherwise the 
most serious consequences may follow. The removal 
of the bone may be effected sometimes soon after the 
fracture; but if, after cutting into the gum, it be found 
too lirmly attached to the surrounding parts, it is bet- 
ter to wait a week or two that nature may loosen it. 
Bones an inch or more in length are often removed. 
Thus that Avhich at first appears to be "only a sore 
mouth," may, if neglected, prove the ruin of a valuable 
horse. 

Fractures are often caused by external violence. A 
severe blow, accidental or otherwise, in the region of 
the roots of the teeth may cause a fracture that will 
necessitate the removal of both the bone and the teeth. 

*' The lower jaw," says Prof. Youatt, " is more sub- 
ject to fracture than the upper, particularly at the 
point between the tushes and the incisor teeth, and at 
the symphysis (of the chin) between the two branches 
of the jaw. Its position, length, and the small quan- 
tity of muscle covering it, especially anteriorly, render 
it liable to fracture. The same circumstances, how- 
ever, comliine to render a reunion of the parts easy." 

The following extraordinary case of accidental frac- 
ture is reported by Surgeon George Fleming ("Veteri- 
narian," 187-1:, p. 094) : 

"In 1805, while stationed near Aldershot, I wv.s 
driving one day in the neighborhood of Farnborough, 
when, in a narrow lane, our progress was somewhat 
checked by a farmers wagon in front, which compelled 
us to travel at a walking pace for some distance. Dur- 



196 FEACTURED JAWS. 

ing this delay my aitention was attracted to the shaft 
horse, which had an enormous tumor on the right side 
of its face. It had such a singukir appearance that I 
dismounted from the carriage and induced the driver 
of the wagon to halt, when I inquired into the history 
of the case, and made an inspection of the tumor. It 
was as large as half a good-sized cocoanut, occupied 
nearly the whole side of the face, and was literally 
a mass of what at first appeared to be fragments of 
bone, but which, on a closer examination, proved to 
be imperfectly developed grinder teeth. The tumor 
looked as if it were composed entirely of tliem. I was 
informed that, when two years old, the foal had taken 
fright and ran away, and in trying to get through a 
gate, a wooden stump ran into its face, making a large 
hole. The hole filled up, the tumor gradually formed 
on it, and since that time these 'bits of bone,' as the 
wagoner called them, were constantly shed from its 
surface. The growth vras so large that the collar wns 
passed over the head with great difficulty. I was so 
much interested in the case that I oiferod to keep the 
animal while the removal of the tumor was attempted; 
but the farmer could not spare it from work at the 
time, and I did not have another opportunity.'' 

The following accounts of cases of fractured jaws 
treated by various surgeons are from Prof. Youatt's 
work, "The Horse" (p. 445): 

'• Surgeon Cartwright had a mare in which the np- 
per jawbone was fractured by a kick at the point 
where it unites with the lachrymal and malar bones. 
He applied "the trephine, and removed many small 
bones. The wound was then covered by adhesive 
plaster, and in a month the parts v\^ere healed. 



MM. REVEL AND BOULEY'S SKILL. 197 

" Surgeon Claywortb reports the case of a mare that 
fell while being ridden almost at full speed, and frac- 
tured the upper jaw three inches above the corner in- 
cisors. The teeth and jaw were turned, like a hook, 
completely within the lower teeth. The mare was cast, 
a balHng iron put into her mouth, and the teeth and 
jaw pulled back to their natural position; she was then 
tied so that she could not rub her muzzle against any- 
tliing, and was fed with bean-meal and linseed tea. 
Much inflammation ensued, but it gradually subsided, 
and at tiie expiration of the sixth week the mouth was 
healed, scarcely a vestige of the fracture remaining. 

'^ An account of a very extraordinary fracture of the 
superior maxillary bone is given in the records of the 
Ro3'al and Central Society of Agriculture in France. 
A horse was kicked by another horse, fracturing the 
upper part of the superior maxillary and zygomatic 
bones, and almost forcing the eye out of its socket. 
Few men would have dared to undertake a case like 
this, but Monsieur Kevel shrank not from his duty. 
He removed several small bones, replaced the larger 
ones, returned the eye to its socket, confined the parts 
with sutures, slung the horse, and in six weeks he was 
well. 

"Surgeon Blaine relates ihat in treating a fracture 
of the lower jaw he succeeded by incasing the entire 
jaw in a strong leather frame. I have myself effected 
the same object by similar means. 

'* Prof Bouley sa^^s {'' Recueil de Medicine Yeteri- 
naire," 1838) that he treated a horse whose" lower jaw 
had been completely broken off at the neck— that is, 
at the point l)ctween the tushes and the corner incisor 
teeth, the dojached bone being held by the membrane 
of the mouth. 



198 FKACTURED JAWS. 

'' The horse was cast, the corner tooth on the left 
side extracted, the wound thoroughly cleansed, and 
the fractured bones brought in contact. Holes were 
drilled between the tushes and the second incisors of 
both jaws, through which brass wires were passed. A 
compress of tow and a ligature, the bearing-place of 
the latter being over the tushes, surrounded the whole. 
Thus the jaws were apparently fixed immovahly to- 
gether. The wires yielded somewhat to the struggles 
of the horse, but the bandage of tow was tightened so 
as to retain the fractured edges in apposition. 

"The wound now began to exhale an infectious odor, 
and gangrene was evidently approaching. M. Bouley 
determined to amputate the fractured portion of the 
jaw, its union to the main bone being apparently im- 
possible. The sphacelated portion of the jaw was en- 
tirely removed ; every fragment of bone that had an 
oblique direction was sawn away, and the rough por- 
tions which the saw could not reach w^re rasped ofi". 

"Before night the horse had recovered his natural 
spirits, and was reaching for something to eat. On the 
following day he ate oats, and no one looking at him 
would have suspected that he had been deprived of his 
lower incisor teeth. The next day he ate hay. In a 
fortnight the wound was nearly healed." 

C. D. House, veterinary dentist, performed an unu- 
sual operation on a seven-year-old horse, the property 
of Mr. J. T. Allen, of Hartford, Conn. In 1876 a 
surgeon (?) made an incision in the right cheek and 
hnocked out a large part of the fifth upper grinder. 
The violence of the operation fractured both the tooth 
and the jaw, imbedding a large fragment of the former 
in the bone above the socket. A year afterward, the 



SKILL VERSUS BRUTALITY. 199 

horse still suffering and discharging matter from the 
nostril, Mr. House was reciuested by Mr. Allen to ex- 
amine and if possible cure him. He failed, however, 
to discover the cause of the dischurge, and it was not 
till the expiration of another year that he determined 
to probe the case to the bottom, the horse in the mean- 
time having suffered as usual. Making an instrument 
of the proper size and shape, he introduced it into the 
nostril, seized the tootli fragment and drew it forth, 
the horse at that instant making a deep expiration, 
which blew out several fragments of bone and a part 
of the root of the tooth. The animal made a good 
recovery.* 

" The Worcester, Mass., Spy for July 13, 1877, says: "C. D. 
House, veterinary dentist, was in the city yesterday, operating 
on the horses of the Hambletoaian "Breeding Stud. A case was 
found where the grinders had been worn rough, and were be- 
sides slightly displaced, so that the horse in eating lacerated the 
lining of the cheek. Another case was where a colt's temporary 
tooth, after being partially forced from its place by the perma- 
nent, had remained fastened by one root, and in such a position 
as to injure the gum while the animal was feeding ; and yet so 
nicjly had the d^'caying tooth been lodged, that its presence was 
only detected by the offensive odor. Several cases of inflamma- 
tion of the gums were found, which were accounted for by the 
presence of tartar. The tartar was removed. 

" Mr. House's mode of operating is unique. He uses no gag, 
and the animal stands free. He passes his hands over the teeth 
of the most vicious horses, and was never yet bitten. He has 



Note.— In a parasjraph of the above note that appeared in the first edi- 
tion of this work, Dr. House, who now holds a diploma, advertised the 
importance of dentistry by depreciating the importance of that great 
ecourge glanders, which Surgeon Fleming describes (1882) as a most repul- 
sive, highly contagious, and incurable malady, very communicable between 
the horse and a:^ species, less so between these and other species, man 
also being frequently infected. Dr. Fleming says the disease was very 
prevalent in London in the winter of 1882. 



200 FRACTURED JAWS. 

Surgeon J. P. Heiitli thus describes a case of frac- 
tured jaw (" VeteriDariau/' 1878, p. 288) : 

" In May last I was called to see a horse that had 
been kicked by another horse. I found a transverse 
fracture of the left side of the lower jaw, between the 
first and second grinders, with lesiuu of the buccal 
membrane. The bone protruded inward, the, tongue 
hung out of the mouth, and a constant flow of saliva 
existed. The animal's appetite was good, but there 
was of course a total inability to masticate. The liorse 
was seventeen years old, but as tlie ftn-mer (Mr. Gale, 
of Exndnster, Devon,) could ill afford his loss, I agreed 
to try to cure him. 

"I procured a wedge-shaped piece of wood, six or 
seven inches long by half an inch thick, which, after 
fitting it between the branches of the jaw, I well be- 
smeared with warm pitch and pressed it tightly be- 
tween the fractured end of the bone. I then fixed 
another piece of wood of the same length, but two 
inches thick, which was also besmeared with pitch, 
outside the fracture, placing a bandage six inches wide 
over the whole, and tying it over the face below the 
eyes. 

operated on Edward Everett, Jud^e Fullerton, Emperor (owned 
by S. D. Houghton, of this city), and other notoriously vicious 
horses." 

The statement about Mr. House's mode of operating is strictly 
true. His control of a horse appears to be a gift. He never 
confines a horse, not even in performino: the operation of castra- 
tion. In an " interview" with a reporter of The New York Stin, 
printed in 1877, in reply to tlie question, " How do you know 
when a horse has the toothache ?" he said : " He tells me that he 
has it." So Mr. House must understand " horse-talk " as well as 
horse-dentistrv. 



SURGEOX HEATH'.S SKILL. 201 

''For the first fortnight I do not think the animal 
took more than a gallon of the thin mashes and gruel 
with which he was supplied ; but after that time the 
use of the muscles of the tongue began to return, and 
he was able to swallow a little. In about three weeks 
he could lick up oatmeal and oilcake gruel made thick, 
and in les6 than a mouth I removed the bandage (al- 
tliough tiie sphuts remained for six weeks), as by this 
time he could swallow a little pulped mangold grass, 
cut into chaff. For nine weeks he could only feed on 
cut fodder, when he was turned out to grass. At the 
present time he is in perfect health, feeding on ordi- 
nary diet and working constantly. The first and sec- 
ond grinders, which were loosened, appear now to be 
as firmly fixed as the others." 

The editor of The Veterinarian" reports the case 
of a pony that came near starving from having a stick 
fiistened in its mouth. l<io fracture of the bone was 
produced, but the account of the case is wortliy of in- 
sertion here notwithstanding that fact, for it illustrates 
a class of mishaps to whicli the horse is subject. He 
says ("Veterinarian," 1855, p. 330): 

"A pony was turned into a pasture, and was not 
seen for several days. The owner found it standing in 
a corner of the field, looking dejected and thin, with a 
small quantity of viscid saliva escaping from its mouth. ' 
He took care of the pony for a few days, during wliich 
time it took nothing but a little water, which it drank 
with great difficulty. Our attendance was now re- 
quested. Examination disclosed a stick about the size 
of one's finder, firmly wedged across the palate, be- 
tween the corner incisors. Its pressure had produced 



202 TREATMENT FOR ABRASED GUMS. 

extensive sloughing, so that the bone was completely 
exposed. The j3ain was so great that the poor animal 
stoutly resisted our efforts to remove the cause of its 
suffering. Tliis, however, was soon done, and the parts 
being cleaned with tepid water, were afterward dressed 
with Tinct. Myrrhge. Little after treatment was nec- 
essary beyond the daily application of the tincture, a 
mash diet, and the substitution of oatmeal gruel for 
plain water." 



CHAPTER XI. 

THE TEETH AS INDICATORS OF AGE. 

Their various ways of Indicating Age.— The "Mark's" Twofold 
Use.— Tlie Dentinal Star.— Marks with too much Cement.— 
Tricks of the I'rade. -Crib-biting.— Signs of Age Independ- 
ent of the Teeth. 

The incisor teetli of the horse, which, as before said, 
differ '-from those of all other animals by the fold of 
enamel which penetrates the body of the crown, from 
its broad, flat summit, like the inverted finger of a 
glove," indicate age (1) by their cutting; (2) by their 
growth; (3) by their shedding; (4) by their marks;* 
(5) by their change of shape ; (6) by their clumge of 
color; (7) by their length, and (8) by the degree of 
their outward inclination. The cutting, growth, and 
sliedding (of the tushes and grinders as well as the in- 
cisors — the cutting and shedding occurring at com- 
paratively regular periods, and the growth being grad- 
ual), indicate age from birth till about the sixth year; 
the marks of the lower incisors from the sixth month 
till the eighth year; those of the upper incisors, though 

* Prof. C. S. Tomes says "the mark exists in Hinparion. but 
not in the earlier proijenitors of the liorse." Prof. O. C. Marsh 
says: "The large canines of Orohipous became gradually re- 
duced in the* later genera, and the characteristic mark of the 
incisors is found only in the later forms." 



204 THE TEETH AS IXDICAIORS OF AGE. 

perhaps less reliable, during the same period, and for 
about four or live years longer (say the twelfth or thir- 
teenth), and the change in shape,* color, and position 
from about the seven tii year till old age. The change 
in the shape of the teeth is caused by their wear and 
growth, the wear counteracting the growth and the 
growth the wear. 

In Ibals and young horses the marks are proi)iibly 
the surest guides by which to judge of the age. One 
peculiarity of them is that, as the teeth wear down, 
they approach the posterior edge. Besides their utility 
in indicating age — being composed of enamel (the ad- 
amantine substance)— they greatly eniiance the dura- 
bility of the teeth— that is, during the first third of 
the horse's life. As a rule the variations in the size 
and appearance of the mark will be 
as follows : 

At six months they are oblong and 
distinct in the centrals, and the 
cavities are plain in the dividers. 

At one year they are short in the 
centrals, are becoming so in the di- 
viders, but are large in the corners. 
At a year and a half they are rep- 
resented by a small spot in the cen- 
trals, are diminished in the dividers, 
but are still large in the corners. 

At two years they are no longer 
visible in the centrals (in some cases 
are even shed) ; are smaller and 
rounder in the dividers, but still 
ihG^i^-Leisering. plaiu in the comcrs. 

* Surg. Cherry says the shape and general character of the 
teeth are better criterions of age than the marks. 




WHAT MAY PUZZLE A XOVICE. 205 

At two years and a half the centrals are shed ; the 
marks are faint in the dividers, but are distinct in the 
corners. 

At three years the permanent centrals are nearly 
grown ; the marks in the dividers are just visible, and 
have become smaller in the corners. 

At three years and a half the marks in the centrals 
are long and very distinct; the dividers are shed, and 
the marks in the corners are fiiint. 

At four yeai-s the marks in the centrals show the 
effects of wear, but are still long and distinct ; the per- 
manent dividers are about grown, and the marks in 
the corner teeth have almost disappeared. 

At four years and a half the marks in the centrals 
are still distinct, while those of the dividers are at 
their best. The contrast between the large permanent 
incisors and the small temporary comer teeth, which 
have lost their marks, is striking at this age. 

At five years the marks in the centrals are getting 
smaller and rounder, but are large and distinct in the 
dividers ; the corners are usually shed at this age. 

"At six years," says Prof. Youatt, "the marks of 
the central nippers are worn out. There will, however, 
still be a difference of color in the center of the tooth. 
The cement filling the hole made by the dipping of 
the enamel will present a browner hue than the other 
part of the tooth. It Tvdll be distinctly surrounded by 
an edge of enamel, and there will remain even a little 
depression in the center, and also around the case of 
enamel ; but the deep holes in tlie center of the teeth, 
with the blackened surface which they present, and 
also the ebvated edge of enamel, avIH have disappeared. 
Persons little accustomed to horses are often puzzled 
here. They expect to find a plain surface of uniform 



m 



THE TEETH AS INDICATORS OF AGE. 



color, and know not what conclusion to draw when 
they see both discoloration and irregular! t}'." The 
marks in tl^e dividers are much reduced in size, but 
those of the corner teeth are large and distinct. 

At seven years the marks disappear from the divider 
incisors, and at eight from the corner teeth. 

Monsieur Girard thus describes the changes in shape 
of the incisors, referring also to the disappearance of 
the marks in the upper teeth : 

"At nine the central incisors become rounded, the 
dividers oval, and the corner teeth narrower. The cen- 
tral enamel (mark) diminishes and 
approaches the posterior edge. 

"At ten the dividers are rounder, 
and the central enamel is very near 
the posterior edge and rounded; at 
eleven they have become rounded, and 
the enamel has disappeared. 

"At twelve the corner teeth are 
rounded. The yellow band is larger, 
and occupies the center of the wear- 
ing surface. 

"At thirteen all the lower incisors 
are rounder; the sides of the centrals 
are becoming longer. The central 
enamel remains in the upper corner 
teeth, but is round and approaching 
the posterior edge. 

"At fourteen the lower central in- 
cisors have a triangular appearance; 
the dividers are becoming long at tneir sides. 

"At fifteen the central incisors are triangular, and 
the dividers are becoming so. 




The forms successive- 
ly assumed by ihe dental 
table of an incisor in con- 
sequence of friction.— ^. 
Chauceaii- 



CAUSE OP THE YELLOW COLOR. 207 

"At sixteen the dividers are triangular, and the cor- 
ner teeth are becoming so. 

*' At seventeen the corner teeth, like the dividers and 
centrals, have become triangular, the sides of the tri- 
angles being equal. 

"At eighteen tlie lateral portions of the triangles 
lengthen in succession— tirst in the centrals, next in 
the dividers, and then in the corners; so that at nine- 
teen the lower centrals are ilattened from one side to 
the other; at twenty the dividers are flattened, and at 
twenty-one the corners also are.'' 

The three following extracts give some idea of the 
difficulties to be encountered in judging the age by 
the teeth. Prof. Youatt says: 

"Stabled horses have the marks sooner worn out 
than those at grass, and a 'crib-biter' may deceive the 
best judge by one or two years. At eleven or twelve 
the lower nippers change their original upright posi- 
tion and project forward. They become of a yellow 
color, the cause of which is that the teeth grow to 
offset their wear ; but the enamel which covered their 
surface when they were young cannot be repaired, and 
that which wears this yellow color in old age is the 
part which was formerly in the sockets. The gums 
recede and waste away, and the tushes wear to stumps 
and project outward.'* 

Surgeon Ewd. Mayhew says ("The Horse's Mouth: 
Showing the Age by the Teeth") : 

"That the teeth of the horse denofe a<zc appears to 
have been a very ancient belief, which the experience 
of centuries has not changed. Within certain limits- 



208 THE TEETH AS INDICATORS OF AGE. 

the belief is well founded, for perhaps no development 
is mere regular than the teeth of the horse, and no 
natural jDrocess so little exposed to the distortions of 
artifice. We are, nevertheless, not to expect that the 
animal carries in its mouth a certificate of birth, writ- 
ten in characters so deep that they cannot be obliter- 
ated or misinterpreted. He who would judge of the 
age by the teetii must study them, and be prepared to 
encounter difficulties. In proportion as he has done 
the one, and is enabled thereby to overcome the other, 
will be his success. The qualified judge alone will 
read the teeth correctly. He will make allowance 
where certain marks are indistinct or absent, and he 
will be cautious in pronouncing an opinion. The vet- 
erinary practitioner knows that the teeth are worthy 
of attention, and he feels that their indications, scien- 
tifically interpreted, will seldom mislead." 

Surgeon J. H. Walsh, in his excellent work, " The 
Horse; in the Stable and in the Field," says: 

"In order to be able to estimate the age of the horse 
by his teeth, it is necessary to ascertain, as nearly as 
may be, the exact time at which he puts up his milk 
teeth, and also the periods at which they were replaced 
by the permanent. Finally it becomes the province 
of the veterinarian to lay down rules for ascertaining 
the age from the degree of attrition which the perma- 
nent teeth have undergone. For these several purposes 
the horse's mouth must be studied from the earliest 
period of his life up to old age." 

Judging the nge by the teeth is even more comi3li- 
cated and difficult than is shown by the foregoing ex- 
tracts. Among other complications worthy of consid- 
eratioji are the following: 




LIKE CREEDMOOH MARKS, HARD TO HIT. ;iU9 

About the ninth year a mark, which is sometimes 
mistaken for the infundibuUim, appears on the central 
incisors. Girard named it the dentinaV^' 
star, but it is also called the fang-hole 
and secondary mark. Dentinal star is 
perhaps the most proper name, for the 
mark is " due to the presence of second- 
ary dentine, into which the remains of 
the pulp has been converted." The con- 
version of the pulp into dentine prevents 
the cavity from becoming a reservoir for food, for 
otherwise it would become such as soon as reached by 
wear ; and it preserves the tooth from decay, afford- 
ing a good illustration of Nature barricading disease. 
The pulp cavity is lined with dentine ; the dentine 
into which the pulp is converted is sometimes called 
osteodentine, and may be distinguished from the for- 
mer by its yellow tint. The star may not afford reli- 
able data by which to judge of the age, but its pres- 
ence is, pi'imd facie evidence that the tooth has been 
worn to the original pulp cavity, f It becomes plainer 
as it approaches the cavity's center, but the bottom 
of the cavity is ultimately reached, which of course is 
hollow. It is visible 8 or 10 years, the depth of the 
cavities varying from about | to 1 inch. 

The marks of some teeth are disproportionately 
composed of cement, a fact Prof. A. Chauveau says he 
is not aware has ever been taken into account in " cal- 

* See note, page viii. 

f Nature tills the canity in proportion as the crown is worn. 
Take two teeth of the same kind, one .fast full-grown, tho 
other worn almost to its neck. In tlio latter the spot is visible, 
and if as mack material is cut from the former as has been wora 
from the latter, its cavity vrill be cat thvovLgh^—John Hunter. 



210 THE TEETH AS IKDICATORS OF AGE. 

culatiDg the progress of wear." Such teeth would soon 
wear out, for there is as much difference iu the density 
of cement and enamel as between cartilage and bone. 

The obliteration of the mark may be hastened in a 
small or medium-sized tooth by the friction of one that 
is abnormally large, while a stunted or dead tooth may 
never lose its mark. 

The more upright the teeth the faster they wear. It 
is said that the crowns will be worn to the extent of a 
quarter of an inch between the fifth and sixth years 
(when they are most upright), while only about that 
quantity of material will wear away between the twen- 
tieth and twenty-fifth years. 

A horse's food is a matter also to be taken into ac- 
count. The mastication of grass, carrots, turnips, 
potatoes, bread, &c., does not cause much wear to the 
teeth. However, when grass is procured by grazing, 
the incisors suffer much friction — caused, not by the 
grass, but by the teeth grinding one another, for they 
meet edge to edge, and are employed in this occupa- 
tion for hours, whereas a "feed" of corn is shelled in 
a few minutes. In the fv)rmer case the incisors suffer 
great friction ; in the latter, the grinders. Again, it is 
said that "horses fed on salt marshes, where the sea- 
sand is washed among the grass, or on sandy plains or 
meadows, are affected by the increased friction of their 
teeth." But no matter how soft a horse's food may 
be, if he is addicted to the vice called "crib-biting," 
his teeth may be ruined before those of the corn-fed 
horse have even lost their marks. 

Several trade tricks are also to be noted. Of "bish- 
oping," Prof. Youatt says : 

^^ Dishonest dealers resort to a method of imitating 



youatt's compliments to bishop. 211 

the mark in the lower nippers. It is called Bislioping, 
from the name of the scoundrel who invented it. The 
horse of eight or nine years is thrown, and with an 
engraver's tool a hole is dug in the now almost plain 
surface of the corner teeth, its shape resembling the 
mark in those of a seven-year-old horse. The hole is 
then burned with a heated iron, and a permanent 
black stain is bft. The next pair of nippers are some- 
times lightly touched also. 

'•An unprofessional man would be easily deceived by 
this fraud, but it cannot deceive the trained eye of the 
horseman. The irregular appearance of the cavity, 
the diffusion of the black stain around the tushes— 
the sharp points and concave inner surface of which 
can never be given again — the marks on the upper nip- 
pers, together with the general conformation of the 
horse, will prevent deception. Moreover, in compar- 
ing the lower with the upper nippers, unless the oper- 
ator has performed on the latter also, they will be 
found to be considerably more worn than the lower, 
the reverse of which ought to be the case. Occasion- 
ally a clever operator will burn all the teeth to a prop- 
erly regulated depth, and then a practiced eye alone 
will detect the imposition." * 

* Koran on the Russians. — Surgeon John C. Knowlson 
makes the fcllowhig open confession (" The Complete Farrier, 
or Horse Doctor," p. 150): " I was hired by Anthony Johnson, 
of Wincolmlee, Hull, as farrier to a number of horses that were 
goinj? to Moscow, Russia. We had a liitb liray, seventeen-year- 
old horse, named Peittum., whose mouth I bishop^d. He passed 
for six years old, was the firsi horse sold, and brought £500, 
Enirlish money ! I only mention this as a caution to hftrsemen." 

Surijeop linowlsou could have evidently beaten the late Pres- 
ident Lincoln in a (wooden) horse trade. 



212 THE TEETH AS INDICATORS OF AGE. 

Of a deception practiced by sellers of two-year-old 
foals, namely, passing off an early two-year-old for a 
late tiiree-year-old, Prof. Youatt says: 

" The age of all horses used to be reckoned from 
May, but some are foaled as early as January. A two- 
year-old foal of the latter date may, if it has been well 
nursed and fed and has had its central nippers drawn 
(that three or four months' time may be gained in the 
appearance of the permanent), be sold at the former 
date for a three-year-old. To horsemen, however, the 
general form of the animal, the little development of 
the forehand, the continuance of the mark in the divi- 
der nippers, its more evident existence in the corner 
ones, and some enlargement or irregularity about fche 
gums, from the violence used in forcing out the teeth, 
are a sufficient security against deception." 

And. again of fo a r-y ear-old foals: 

"Now, more than at any other time, will the dealer 
be anxious to put an additional year upon the animal, 
for the difference in strength, utility, and value be- 
tween a four-year-okl colt and a five-year-old horse is 
very great. But the lack of wear in the central and 
divider nippers, the small size of the corner ones, the 
little growth of the tnshes, the low forehand, the leg- 
gin ess of the colt, and the thickness and little depth of 
the mouth, will at once detect the cheat." 

The following is Prof Yonatt's description of crib- 
biting and its effect on the teeth (" The Horse," pp. 
511, 519): 

"The horse lays hold of the manger with his teeth, 
violently extends his neck, and then, after some con- 



COLICKY CKIB-BITERS. 213 

viilsive action of the throat, a slight grunting is heard, 
accompanied by a sucking in of air. It is not an effort 
iit simple eructation, arising from indigestion, but is 
merely the inhalation of air. It tukes place with all 
kinds of diet, and when the stomach is empty as well 
as when it is full. 

<• The effects of crib-biting are plain enough. The 
teeth are worn away and occasionally broken, and in 
old horses to a very serious degree. Sometimes graz- 
ing is rendered difficult or almost impossible. Corn is 
ofren wasted, for the horse will frequently 'crib' with 
his mouth full of it, and the greater part of it will fall 
over the edge of the manger. Much saliva escapes also, 
which imi)airs digestion. Crib-biting horses are more 
sul)jcct to colic than others, and to a species difficult 
of treatment and frequently dangerous. 

'"The only remedy is a muzzle, with bars across the 
bottom sufffciently wide to allow the horse to pick up 
his corn and pull his hay, but not to grasp the edge of 
the manger. Some recommend turning out for live or 
six months; but this will never succeed except with 
young horses, and rarely with them. The old crib- 
biter will substitute the gate for the manger. AVe have 
often seen him galloping across the Held for the mere 
object of having a gripe at a rail." 

Prof Youatt further says that the vice is a species 
of unsoundness, having been so decided in the courts. 
It is often the result, he says, of imitation, but oftener 
the consequence of indigestion. Mischief, he says, is 
another cause of it. 

The mouth, it is said, is broader at seven years of 
age than at any other time; but, so far as judging the 
ac^e i:> concerned, this fact (assertion) is of little prac- 



214 THE TE2TH AS INDICATORS OF AGE. 

tical 1133. The facts that follow, however, are of more 
or les3 use, aad are worthy of perusal. Prof. Youatt 

says: 

'' The indications of age, independent of the teeth, 
are deepening of the hollows ovei^ the eyes ; wrinkles 
over the eyes and about the mouth ; gray hairs, par- 
ticularly over the eyes and about the muzzle; the 
countenance and general appearance; thinness and 
hanging down of the lips ; sharpness of the withers; 
sinking of the back; lengthening of the quarters, and 
the disappearance of windgalls, spavins, and tumors of 
every kind. * * * At nine or ten the 'bars' of 
the mouth become less prominent, and their regular 
diminution will indicate increasing age." 

Of another deception Prof. Youatt says: 

" We form some idea of the age of the horse by the 
depth of the pits above the eyes. There is at the back 
of the eye a quantity of fatty substance, on which it 
may revolve without friction. In aged horses, and in 
diseases attended with general loss of condition, much 
of this disappears. The e^^e becomes sunkeu, and the 
pit above it deepens. Dishonest dealers puncture the 
skin, and, with a tobacco-pipe or tube, blow into the 
orifice till the depression is almost filled. This, with 
the aid of 'bishoped' teeth, may deceive the unwary. 
The fraud may be easily detected, however, by press- 
ing on the part.'*^ 

"Frank Fores^-er" (William Henry Herbert), says 
(" The Horse of America," vol. i, p. 72) : 

" Much stress is laid by many persons on the depth 
of the supra-orbital cavities, and more yet on the length 
and extreme protrusion of the nippers beyond the 



Pliny did not compile Yarro (B. C. 116j and 
Columella (A. D. 42) carefully. Varro (Book IL, 
Cap. YII.) says : "It is by the teeth that they find 
out the age of a horse." He then describes the 
shedding of the teeth, concluding as follows : "Others 
grow in their place, which, hollow at first, fill up in 
the sixth year," etc. The error about the cavities 
filling up stands to this day. Unlike the pulp cavi- 
ties, they are not filled by nature with tooth ma- 
terial ; they are obliterated by wear. C: lumella 
(Book VI., Cap. XXIX.) not oidy describes the 
marks, but the shedding of the molars also. In 
Latin he says : " Intra sextum deinde annum, molares 
superiores cadunty So the error of Aristotle about 
the non-shedding of the mohirs did not stand till 
the sixteenth century. (See page 69.) Palladius 
(about A. D. 400) and Vegetius (about the same 
time) describe both the marks and the shedding of 
the molars. Vegetius speaks of the wrinkles in the 
upper lip, the numl)pr of wrinkles indicating the 



number of 3^ears, and also the black spots in the 
middle of the teeth about the twelfth year. In con- 
clusion he says : " Finally, the number of wrinkles, 
the sadness of the countenance, the stupor of the 
eyes, the baldness of the eyelids, the dejection of 
the neck, and the lassitude of the whole body indi- 
cate age." (Book IV., Cap. V.) I have never seen 
what could be called a description of the wrinkles in 
any other book, but my attention was called to them 
by Dr. Wm. Wilson, of Jersey City, N. J., in 1881. 
Vegetius Renatus, PuhUiis, is often confounded with 
Vegetius Renatus, Flavius, a military author. Ye- 
getius Avrote on veterinary science ; Varro, Columel- 
la and Palladius on agriculture. Fragments of the 
works of Apsyrtus (or Absyrtus), the Greek veter- 
inarian (about A. D. 830), are extant, but I have 
never seen anything of his on age. He described 
glanders, fevers, epizootic influenza, dental cysts, 
etc. (See Jouunal of Comparaiive Medicine and 
Surgery for January, 1881, page 19.) 



SPANISH HORSES AND MULES — ANCIENTS. 215 

gums, as also on hollowness of back. I have seen colts 
— got hy aged stallions — having all tliese indications 
of age before they had a full mouth ; and with cavities 
and hollow backs before they had got colt's teeth." 

Surt^eon Brandt, who thinks shape indicates age aa well after 
the eiglith year as marks do before, says (" Age of Horses"): — 
*' Some breeds, the Spanish for instance, require a longer time 
to develop than others. The bones appear to be harder, the 
teeth chang-e somewhat later, and wear more slowly; some- 
times, after the fifth year, they appear one or two years younger 
than they are. The age of crib-biters can be told by the corner 
teeth, which are seldom injured. Should this be the case, how- 
ever, add as many lines as are needed to make them the natural 
length. The lioi-se is as many years younger as the teeth are 
lines too short. The front teeth are frequently worn away 
earlier when horses have been fed on unshelled corn. 

" The age of mules cannot be ascertained with the same ac- 
curacy as that of horses. After their eighth year they usually 
appear younger than they are," 

Wofte.—C. F. Hoeing. M.R.C V.S. (Jersey City, N.J.) says the fact that the 
marks indicate age was discovered by Prof. Pessina of Vienna in 1818-20. 

The ancients appear to have known nothing about the marks. Aristotle 
(His. Animals, Bohu's trans., pp. 170 1) says that before casting its teeth a 
horse has its mark, but not afterward. After casting them age is not easily 
told, but is usually ascertained by the canines, which in riding-horses are 
generally bit-worn ; these teeth are called the marking teeth. (That is they 
are marked by wear. They have no natural marks. Sec p. 09.) 

Xenophon, who finds use for tushes in bridling a horse— pressing the lip 
agiinst them— says that in buying a horse, " to avoid being cheated, lot it 
not escape notice what his age is ; if he has not the foal teeth, he can neither 
give pleasure with anticipated exertion nor be easily disposed of." (o. 719.) 

Pliny says age is indicated by the eniption and shedding of the incisors 
(giving accurate dates) ; then hy the projecting of i\\Q teeth, the giayness 
of the eyebrows, aid the depth of the pits around them. (Vol. iii. p. 60.) 

Pliny compiled from Varro, Columella, and many others. Would they 
an fail to mention the marks if they knew ans'thing about them ? 

Erroneous and Extraordinary S'atements by Pliny.— Tlav-^c?,'' teeth grow 
whiter with age. If a horse is gelded bt'fore it chani:^es its teeth it never 
Bhe.ls them. No animal sheds the molars. Men have more teeth than 
women. All men, except the Turdnli, have 32 teeth. Some persons have ,t 
continuous bone in place of teeth. Human te;'th contain venom ; they tar- 
nish a mirror and kill unfledged pigeons. Zodes had a set of teeth at 104. 



CHAPTER XII. 

THE TRIGEMINUS OR FIFTH PAIR OF XERVES. 

Its Nature and tlie Relation it bears to the Teeth. — Its Course in 
the Horse and in Man. 

The tb read-like nerves of the teeth are derived from 
the superior and inferior maxillary branches of the 
trigODiinns or fifch pair of nerves. In the horse these 
branches are four or five times as thick as a ribbon 
and about five-eighths of an inch wide. The ophthal- 
mic branch is smaller and shorter, its course extend- 
ing only from the brain to the eye, while that of the 
two former extends to the lips, running parallel to and 
about an inch from the roots of the grinder teeth,* 

The description of the trigeminus and its course is 
from a lecture by Prof, Youatt to veterinary students, 
and may be found in '-'The Veterinarian" for 1834 
(p. 121). In the first part of the lecture the nature of 
the trigeminus — its double origin and function — is 
expatiated upon, a summary of which is that the sensi- 
tive and motor roots, are contained within the same 
sheath ; that the sensitive root is so mucli larger and 
its fibrils so much more numerous than tlie motor tliat 

* For the preparation of an anatomical specimen showing the 
jreneral course of the tripfominns, I am indebted to Prof. J. M. 
Heard, of the New York College of Veterinary Surgeons. 



THE TWO ROOTS. 217 

it may still bs callod the sensitive nerve of the face; 
that the trigeminus is the only nerve of the brain that 
bestows sensiljilit y to the face, excfpt a few branches 
from the cervicals, which may be traced to the lower 
part of it; that there are some anatomical facts which 
incontestably prove that the motor nerve exists : that 
Sir Charles Bell laid the root of the trigeminus bare in 
an ass immediately after the animal's death, and that 
on irritating the nerve the muscles of the jaw acted 
and the jaw closed; that he divided the root of the 
nerve in a living animal, and the jaw fell;* that he 

* " Re-establisiiment of Sensibility after Resection 
OF Nerves. — A memoir by MM. Arloing and Tripier was read 
before the Frencli Academy, November 28tb, on the effect of re- 
section of certain nervous trunks. Clinical facts have several 
limes shown that after wouncls which have altered or destroyed 
a portion of a nerve, sensibility returns in the integuments to 
which the nerve is distributed. MM. Arloing and Tripier made 
nervous resections in dogs, and saw sensibility reappear after a 
certain time in the integuments to which the branches of the 
nerve were distributed, and in the peripheral end of the nerve 
itself." — Popular Science Recieic, 1SC7. 

" How Motor-Nerves End in Non-strtated Muscular 
Tissue. — A very valuable communication stating the results of 
M. Ilenocque's researches has been published in " I'Archives de 
Physiologie," and may be thus abstracted : 1. Tlie distribution 
of the nerves in smootli muscle is not only identical in man and 
otlier vertebrate animals in which it has been observed, but is 
essentially similar to all the organs containing smooth muscle. 

2. Before terminating in the smooth muscle, the nerves form 
three distinct plexuses or networks— (a) a chief or fundamental 
plexus, containing numerous ganrrlia, and situated outside the 
smooth muscle ; (h) an intermediate plexus ; and (c) an intra- 
muscular plexus, situated mthin the fasciculi of smooth fibers. 

3. The tern.inal fibrils are everywhere identical. They divide 
and subdi\ido dfVhotomoiisly. or anastomose, and terminate by 
a slight swelling or knob, or in a punctiform manner. The ter- 

10 



218 THE riFTil PAIR OF NERVES. 

divided the superior maxillary branch on both sides, 
the animal losing the power of using the lips; that 
Mr. Mayo divided the root of both the superior and 
inferior maxillary, the result being that the lips no 
longer remained in perfect apposition, and the animal 
ceased to use them in taking up his food; that the 
sensitive root, or a portion of it, after entering the cav- 
ernous sinus, swells out into or passes through a gan- 
gUon, and that the motor root can be traced beyond 
the ganglion, uniting afterward with its fellow and 
forming the perfect nerve; that the ganglion, being 
composed of sensitive fibrils only, resembles a brain. 

minal swellinor appears to occupy diflferent parts of the smooth 
muscular fiber, but most frequently to be in the neighborhood 
of the nucleus, or at the surface of the fibers, or, lastly, between 
them." — The Monthly Microscopical Journal, 1870. 

" Structure of Nerves. — M. Roudanoosky says that the 
primitive elements of nerves are tubes having a pentagonal or 
hexagonal configuration. As to their constitution, he says that 
every nerve has a substratum of brain-matter, and also of the 
spinal marrow, and probably of the ganglionic matter also. The 
gray matter, he says, is the fundamental nervous substance, and 
plays the principal part in the functions." — ''Veterinarian,'* 
1865, p. 313. 

In a letter to his brother, G. J. Bell, written in 1807, Sir 
Charles says: "I consider the organs of the outward senses as 
forming a distinct class of nerves. I trace them to correspond- 
ing parts of the brain, totally distinct from the origin of the 
others. I take five tubercles within the brain as the internal 
senses. I trace the nerves of the nose, eye, ear, and tongue 
to these. Here I see established connection ; there, the great 
mass of the brain receives processes from the central tubercles. 
Again, the great masses of the cerebrum send down processes 
or crura, which give off all the common nerves of voluntary mo- 
tion. I establish thus a kind of circulation, as it were," — Medi- 
cal Gazette. 



THE COURSE OF THE is^ERVE. 219 

Prof. Youatt's description of the course of the tri- 
geminus is as follows: 

"The trigeminus has been described as springing 
b}" a mnltitudo of filaments from the crura cerebelli, 
and fortliwitli running for safety into the cavernous 
sinuses, and there suddenly enlarging into or passing 
through a ganglion. The nerve, as its name implies, 
divides into three parts, the division taking place in 
the cavernous sinus, after the superior or sensitive 
root has been joined by the inferior or motor root. 
Each part, before it leaves the cranium, assumes a dis- 
tinct investment of dura mater. The branches are 
named, from the parts to which they are destined, the 
Ophthalmic, the Superior Maxillary, and the Inferior 
Maxilhny. 

"The ophfhalmic is the smallest of tlie three. It is 
formed witliin the sinus, where it is in conjunction 
with the superior maxillary, which it soon leaves, and, 
passing through the foramen lacerum into the orbH, 
subdivides and forms three distinct branches — the 
Supra-orbital (the frontal), the Laclirymal, and the 
Lateral Nasal (the nasal). The supra-orbital climbs 
behind the muscles of the eye, ginng filaments to the 
rectus superior and the superior oblique, and some 
also to the fatty matter of the eye. The main branch, 
escaping through the superciliary foramen, is soon lost 
in ramifications on the elevator of the superior eyelid, 
the integument of the forehead, and the periosteum. 
The lachrymal, as its name implies, is chiefly concerned 
with the lachrymal gland; a few ramifications, how- 
ever, are sent to the conjunctiva and also to the ciliary 
glands of the upper eyelid, while a distinct twig of it 
passes ont at the angle between the zygoma and the 



220 THE FIFTH PAIR OF i^EKVES. 



frontal orbital process, where it anastomoses with the 
sapra-orbital and with ram ilications from the superior 
maxillary. It is also lost on the integument and 
muscles of the forehead. The lateral nasal is the 
largest of the three. Almost at its beginning we ob- 
serve the filaments that help to form the Ophthalmic 
Ganglion. They are more numerous and more easily 
traced in some of our domesticated animals than in 
others, and the ganglion itself is differently developed, 
but for what physiological purpose I know not. It is 
comparatively larger in the ox than in the horse, and 
sends more filaments to the iris. Four distinct fila- 
ments may be traced in the ox, but seldom more 
than two in the horse or the dog. To these fila- 
ments others of the ophthalmic, that have not passed 
through the ganglion, afterward join themselves; so 
that the ciliary are also minute compound nerves of 
motion and sensation.* 

* " The best account, however, of this is ^ven by Dr. Jonas 
Quain (' Quain's Anatomy,' p. 7fi8). He considers the ganglion 
as a center of nervous influence — a little brain, as it were — and 
the filaments which some anatomists describe as composing, he 
speaks of as branches given out from it. ' It lies,' says he, 
' within the orbit, about midway between the optic foramen and 
the globe of the eye. and is inclosed between the external rectus 
muscle and the optic nerve. It is exceedingly small and, owing 
to its being imbedded in the soft adipose tissue which fills the 
interstices of the different parts within the orbit, difficult to find. 
Its branches are the following: From its anterior border from 
sixteen to twenty filaments issue, which proceed forward to the 
surface of the sclerotic, and pierce it through minute foramina. 
These are the ciliary nerves. In their course to the globe of the 
eye they are joined by one or two filaments derived from the 
nasal nerve, but they do not form a plexus fan interlacement). 
They become, however, dispersed or divided into two fasciculi, 
one above and the other below the optic nerve, the latter being 



THE OPHTHALMIC NERVE. 221 

"The ophthalmic nerve, after running between the 
rectus superior and the retractor muscles, gives a 

the more numerous. They pass between the choroid membrane 
and the conti<raous surface of the sclerotic — lodg-ed in grooves in 
the hitter— and on reaching the ciliary lioament, i^ierce it, a few- 
appearing to be lost in its substance, while all tlie rest pass in- 
ward and ramify in the iris. From the posterior border of the 
ganglion, which seems as if terminated by two angles, two 
branches issue, one of which passes backward and upward to 
the nasal branch of the ophthalmic nerve, ap[»earing to be the 
medium of communication between the ganglion and the rest of 
the ganglial system, by being prolonged to the carotid plexus. 
The other, the shorter branch, passes downward and backward 
to the inferior oblique branch of the motor nerve of the eye.' 

" For my own part," says Prof. Youatt, " I am now disposed 
to be very much of Dr. Quain's opinion. It was not fittinf? that 

the motions of the iris should be under the control of the will 

they should respond to the varying intensity of the light."— TT. 
Toiiati in " Veterinarian" for 1S3G, p. 49. 

Mous. Cuvier says : " It divides into two ramifications, one of 
which proceeds toward the optic, unites with the small branch 
of the third pair, and by this union produces a nervous enlarge- 
ment called the lenticular or ophthalmic ganglion. This gan- 
glion usually sends off the ciliary nerves, disposed in two bun- 
dles. They are each composed of several filaments, which enter 
the globe of the eye obliquely. The iris receives a great num- 
ber of small ramifications from the ciliary nerves, which, after 
having ]ier{orated the sclerotic and passed around the choroides 
longitudinally, like ribbons, but A\ithout penetrating it, are lost." 
— " Comparative Anatomy," Vol. II, p. 206. 

Prof. W. Percivall says: " Upon the outer side of the optic 
nerve, between it and that part of the motor oculi from which 
the branch nerves spring, is situated the ophthalmic ganglion. 
This little body is principally constituted of branches from the 
third pair, but it receives a filament or two from the sixth. The 
nervous threads transmitted by the ganglion surround the sheath 
of the optic nerve, and pursuing their course over it, penetrate 
the globe of tlte eye, and run to be dispersed upon the iris."— 
"Anatomy of the Horse," p. 3S6. 



222 THE FIFTH PAIR OF KERVES. 

bniucli to the ^membrana nictitans/ and then takes a 
singular course. Some ramifications go to the frontal 
sinuses and the foramina, and, piercing the orbit of 
the eye for this purpose, present a beautiful view in 
young animals, particularly the sheep. The main 
branch then enters the cranium again through the 
internal orbital foramen, passes under the dura mater, 
returns through the cribriform plate, and raiiiifies on 
the membrane of the nose, sending some branches as 
low as the false nostril and alae. 

" The superior maxillary nerve, or second branch of 
the trigeminus, contains little that is peculiar to or 
has a practical tendency in quadrupeds. The different 
situation and conformation of the bones of the face 
cause the principal or only variation in the distribu- 
tion of this branch in the biped and the quadruped. 
It leaves the crauium through the foramen rotundum, 
and at the base of the skull gives off small ramifica- 
tions to the inner canthus of the eye, the antrum, and 
the two posterior grinder teeth. It also supplies the 
lateral portion of the nasal cavity through tlie spheno- 
palatine foramen, while filaments are given off from 
the origin of the trunk to the temporal muscle. A 
branch also runs along the upper border of the septum 
nasi to the palate, and a larger branch, which trav- 
erses the palate in company with its blood-vessels, 
passes tlirough the foramen incisivum to the upper 
lip. The main trunh of the nerve now enters into the 
superior and exterior foramen, in the hiatus between 
the palatine bone and the tuberosity of the superior 
maxillary bone, leading into a bony canal (easily traced 
in the horse) between the maxillary sinus and the an- 
trum, and appearing as a great pillar passing through 
the palatine sinuses in the ox. It traverses this canal, 



THE GOOSE'S FOOT. 223 

and at length emerges on the face through the fora- 
men infra-orbitariiim, and under the levator lahii supe- 
rioris muscle. It no sooner escapes from this canal 
than it forms the 'pes anserinus' (the goose's foot, for 
it divides something like the foot of this bird). It 
anastomoses with or receives numerous branches from 
the seventh pair, and forms an intricate plexus about 
the lower part of the face and muzzle. The nerves, 
however, are wisely and beautifully interwoven, for the 
lips, being the seat of touch, require all the flexibility 
and more than the sensibility of the human hand. 

"Tlie inferior mnxillarij nerve, or third branch of 
the trigeminus, emerges from the cranium through 
the foramen lacerum basis crauii, and very soon gives 
o^ four important branches. The lirst branch, reck- 
oning posteriorly, proceeds backward below the con- 
dyle of the jaw, where it divides into two portions. 
The first runs up to the parotid gland, ramifies into 
many filaments, and unites with the seventh pair. It 
dips deep into and principally supplies the temporal 
muscle, and penetrates and is distributed through the 
masseter muscle. In this division there seems to be 
concentrated the greater part of the motor fil^rils of 
the trigeminus, for these are muscles of extensive and 
powerful action. There are few muscles of the frame 
that are oftener or more powerfully employed than 
those concerned in mastication ; but with the motor 
fibrils those of sensation are doubtless conjoined. 

" The second branch is a long and slender one. It 
first dips into the pterygoideus muscle, which is sup- 
plied by it; consequently it is here also a motor as well 
as a sensitive nerve. It then passes around or behind 
the tuberosity of the upper jaw, supplying the bucci- 
nator muscle— possibly with sensitive fibrils alone, for 



224 THE FIFTH PAIR OF NERVES. 

others go to this muscle from the seventh pair. In 
the buccinator these fibrils are usually lost; but some- 
times a few of them ma.y be traced to the lower lip. 

" The third brancli, in the order of its being given 
off, is the dental nerve. This is generally considered 
the continuation of the trunk of the inferior maxillary 
nerve. It passes across the pterygoideus and enters a 
canal (the dental canal), on the inner face of the lower 
jawbone, near the upper edge, and at the bending or 
angle of the jaw. It takes its course along the interior 
of the bone (tlie canal), close to the roots of the teeth, 
and sends out filaments to each of them. Emerging 
through the lower maxillary foramen, it divides into 
two branches, one of which is distributed in numerous 
ramifications on the outside of the lower lip, and the 
other in fewer ramifications on the inside. These are 
evidently sensitive fibrils, the power of motion being 
derived from the seventh pair of nerves. 

" The fourth branch in point of order, but which 
does not enter the ' dental canal,' is the gustatory or 
Ungual nerve, the largest of the four. It is singularly 
flat, like a little ribbon. It runs along the inside of 
the lower jaw, and a branch of it enters a foramen in 
the jaw to supply the roots of the incisor teeth ; but 
the main nerve, proceeding obliquely downward, gives 
fibrils to the submaxillar}^ glands, and to the glands 
and muscles at the base of the mouth generally. These 
fibrils form true ^ilexuses about the salivary glands and 
the muscles of the tongue. They anastomose freely 
with the twelfth pair (the linguales or motor nerve of 
the tongue), as the twelfth had already done with the 
seventh (the 'portio dura'). The gustatory branch 
penetrates the substance of the tongue between the 
stylo and genio-glossal muscles, passing obliquely to 



KICH PLEXUSES AND LOOPED FILAMENTS. 225 

the surface of the tongue, and terminating in the pa- 
pilla?. The pai)illre, thus endowed with nervous influ- 
ence, are the seat of the sense of taste." 

Of the fifth nerve (in man and in the horse) Prof. 
Owen (quoting partly from Dr. Swan), says ("Odon- 
tography," vol. i, pp. Ixv-vi) : 

" 'I'he nerves of the teeth are derived from the tri- 
geminal, or fifth pair, of which the second division sup- 
plies tiiose of the upper jaw, the third division those 
of the lower. In the human subject, the three dental 
branches of the infra-orbital nerve intercommunicate 
by their primary branches, from which, and from a 
rich plexus formed by secondary branches upon the 
membrane lining the antrum, two sets of nerves are 
sent off to the alveolar processes of the upper jaw; one 
set {rami dentales) supplies the teeth, the other {rami 
gingivales) the osseous tissue of the gums. The latter 
agree in number with the intervals of the teeth, as the 
proper dental nerves do with the teeth themselves. 
These two sets are not, however, so distinct but that 
some intercommunications are established between the 
fine branches sent off in their progress to the parts 
they are specially destined to supply. Tlie rami den- 
tales take the more direct course (through the middle 
part of the osseous tissue to the teeth) penetrate the 
orifices of the fangs, and form a rich plexus with 
rhomboidal meshes upon the coronal surface of the 
pulp, the peripheral elementary filaments returniug 
into the plexus by loops. In the lower jaw^ the dental 
nerve, besides supplying the proper nerves to the teeth, 
also forms a rich plexus, in which it is joined by some 
branches frcrm the division of the nerve that afterward 
escapes by the foramen mentale, and from this plexus 



226 THE FIFTH PAIR OF SERVES. 

the cancellous tissue of the bone and the vascular 
gums are supplied. * * * * 

"In the horse the maxillary plexus is most devel- 
oped above and between the alveoli of the three pre- 
molar teeth. It is less complex where it supplies the 
molar teeth, their alveoli, and the gums. In the 
lower jaw of tlie horse a very rich plexus begins to be 
formed in the cancellous substance of the bone by 
branches of the dental nerve, soon after its entry into 
the canal." 



VOCABULARY. 



Note. — The definitions, where not otherwise credited, are 
from "Duuglison's Medical Dictionary." 

A. 

Ala. (plural, alae). Projections from the median line ; as the 
alae nasi, alte of the uterus, &c. 

Albumen. An important organic compound. The character- 
istic ingredient in the white of egg ; abounds in the serum 
of the blood, in chyle, lymph, skin, muscles, brain, and the 
juice of flesh; in small quantity in most vegetable juices, 
and in Bright's disease in considerable quantity in the urine. 
It is the foundation, says Liebig, of the whole series of pecu- 
liar tissues which constitute those organs v.iiich are the 
seat of all vital actions. C. F. CJiandler. 

Alve'olar Arches are formed by the margins or borders of 
the two jaws, wliich are hollowed by the alveoli. 

Alveolar Arteky, arises from the internal maxiUary, de- 
scends behind the tuberosity of the upper jaw, and gives 
branches to the up])er molar teeth, gums, periosteum, mem- 
brane of the maxillary sinus, and buccinator muscle. 

Alveolar Border. The part of the jaws that is hollowed by 
the alveoli. 

Alv:eolar Membranes are very fine membranes, situated be- 
tween the teeth and alveoli, and formed by a portion of the 
sac which incloses the tooth before it pierces the gum. By 
some this membrane has been called the ' alveolo-dental 
periosteum*.' 

Alveolar Vein. TLis has a distribution similar to the artery. 



228 VOCABULARY. 

Alve'olus (pi. alveoli). The alveoli are the sockets of the 
teeth, into which tiiey are, as it were, driven. Tiieir size 
and shape are determined by the teeth which they receive, 
and they are pierced at the apex by small holes which give 
passage to the dental vessels and nerves. 

Anastomo'sis (' a mouth '). Commmiication betv/een two ves- 
sels. By considering the nerves to be channels, in which a 
nervous fluid circulates, their communication likewise has 
been called anastomosis. By means of anastomoses, if the 
course of a fluid be arrested in one vessel, it can proceed 
along others. 

AnisodaC'tyle. Hoofed quadrupeds with toes (on the hind- 
feet at least) in uneven numbers, as one, three, or five, the 
latter being manifested by the Proboscidians. All these have 
a simple stomach and an enormous caecum. Examples : 
Horse, tapir, rhinoceros, elephant. R. Owen. 

Ante'rior {ante ' before '). Great confusion has prevailed with 
anatomists in the use of the terms before, behind, &c. 

(A practical definition of anterior appears to be CI) parts 
in front, supposing the body to be equally divided longi- 
tudinally from right to left ; (2) parts nearest the operator, 
parts beyond being posterior?) 

Antrum. A cavern. A name given to certain cavities in 
bones, the entrance to which is smaller than the bottom. 

Antrum of Highmore. A deep cavity in the substance of the 
superior maxillary bone, communicating with the middle 
meatus of the nose. It is lined by a prolongation of the 
Schneiderian membrane. 

Arach'noid Membrane. A name given to several mem- 
branes, which, by their extreme thinness, resemble spider- 
webs. The moderns use it for one of the membranes of the 
brain, situate between the dura mater and pia mater. It is a 
serous membrane, composed of two layers, the external being 
confounded, in the greater part of its extent, with the dura 
mater, and, like it, lining the interior of the cranium and spi- 
nal canal ; the other is extended over the brain, from which 
it is separated by the pia mater, without passing into the 
sinuosities between the convolutions, and penetrating into 
the interior of the brain by an opening at its posterior part, 
under the ' corpus callosum.' It forms a part of the investing 



AX arjIed Q:ADii:rcD. 229 

eheath of nerves, as ihoj pass from tlie encephalic cavities, 
Its chief uses seem to be to envelop and, in some measure, 
protect the brain, and to secrete a tiuid for the purpose of 
keeping it in a state best adapted for the performance of its 
functions. 

Are' OLA. A diminutive of 'area.' Anatomists miderstand by 
areolae the interstices between the fibers composing organs, 
or tiiose existing between laminae, or between vessels which 
interlace with each other. 

Argen'ti Nitras. Nitrate of silver ; lunar caustic. The vir- 
tues of nitrate of silver are tonic and escbarotic. It is given 
in chorea, epilepsy, &c.; locally, it is used in various cases as 
an escharotic. Dose, gr. 1-8 to gr. 1-4, in pill, three times 
a day. 

Armadil'lo. (So called from being protected or armed by a 
scaly covering like the plate armor of the middle ages.) A 
genus of South American quadrupeds, belonging to the order 
of edentata, and characterized by a defensive armor of small 
bony plates, covering the head and trunk, and sometimes the 
tail. Br (Hide. 

Articula'tion. The union of bones with each other, as well 
as the kind of union. Articulations are generally divided 
into two kinds — movable and immovable. The articulations 
are subject to a number of diseases, which, are generally some- 
what severe; they may be physical, as wounds, sprains, lux- 
ations, &c., or they may be organic, as ankylosis, extraneous 
bodies, caries, rheumatism, gout, &c. 

At'rophy. Progressive and morbid diminution in the bulk of 
the whole body or of a part. Atrophy is generally symp- 
tomatic. Any tissue or organ thus aflfected is said to be 
* atrophied.' 

AuRic'uLAR. (Tiie ear. ) That which belongs to the ear, espe- 
cially the external car. 

B. 

Batra'chia. An order of reptiles including toads, frogs, and 

salamanders. Brande. 

One of the five great classes into which vertebrate animals 

are usually, divided, though some writers have reduced the 

class to the rank of an order of reptiles, a class with which 



230 VOCABULARY. 

tliey are popularly confounded, Tlie batracLians are cold- 
blooded and oviparous, and in most living species are with- 
out scales, and the blood is partly aerated tlirougli the skin. 
The young, for the most part, breathe by gills like those of 
fishes; they assume a fish-like form (as the tadpole), and 
finally, when adult, with few exceptions, lose their gills and 
breathe by lungs, like true or scaly reptiles. They generally 
have limbs, but not always. Johiison's N. U. Ci/c. 

Bi'furcation . (A fork.) Division of a trunk into two 
branches, as the bifurcation of the trachea, aorta, &c. 

Buccal. That which concerns the mouth, and especially the 
cheek. 

C. 

C^CUM. The blind gut ; so called from its being perforated at 
one end only. That portion of the intestinal canal which is 
seated between the termination of the ileum and beginning 
of the colon, and which fills, almost wholly, the right iliac 
fossa, where the peritoneum retains it immovably. Its length 
is about three or four fingers' breadth. The ileo-caecal valve, 
or valve of Bauhin, shuts off all communication between it 
and the ileum, and the * Appendix verraiformis cseci* is at- 
tached to it. 

In the horse the caecum (water stomach) will hold four gal- 
lons. A horse will drink at one time a great deal more than 
his stomach will contain ; but ev^en if he drinks a less quan- 
tity, it remains, not in the stomach or small intestines, but 
passes to the caecum, and is there retained, as in a reservoir, 
to supply the wants of the system. Youatt. 

Cal'culus. a diminutive of ' calx,' a lime-stone. Calculi are 
concretions, which may form in every part of the animal 
body, but are most frequently found in the organs that act 
as reservoirs, and in the excretory canals. They are met 
with in the tonsils, joints, biliary ducts, digestive passages, 
lachrymal ducts, mammae, pancreas, pineal gland, prostate, 
lungs, salivary, spermatic, and urinary passages, and in the 
uterus. The causes which give rise to them are obscure. 
Those that occur in reservoirs or ducts are supposed to be 
owing to the deposition of the substances, which compose 
them, from the fluid as it passes along the duct ; those which 
occur in the substance of an organ are regarded as the pro- 



THE USES OF BONE CELLS. 231, 

duct of Bome chronic irritation. Their generul eflfect is to 
irritate, as extraneous bodies, the parts vvitli which they are 
in contact, and to produce retention of the tluid whence they 
have been formed. The symptoms differ, according to the 
sensibility of the organ and the importance of the particular 
secretion whose discharge they impede. Their ''solution' is 
generally impracticable. Si)ontaneous expulsion or extrac- 
tion is the only way of getting rid of them. 

Cancel'li. ' Lattice-work.' The cellular cr spongy texture of 
bone, consisting of numerous cells, communicating with each 
other. They contain a fatty matter, analogous to marrow. 
This texture is met with principally at the extremities of 
long bones, and some of the short bones consist almost wholly 
of it. It allows of the expansion of the extremities of bones, 
without adding to their weight, and deadens concussions. 

Can'dla. Diminutive of canna, ' a reed.' A small tube of gold, 
silver, platinnm, iron, lead, wood, elastic gum, or gutta- 
percha, used for various purposes in surgery. 

Cap'illary (from capillus, ' a hair '). Hair-like ; small. 

Capillary Vessels are the extreme radicles of the arteries 
and veins, which together constitute the capillary, interme- 
diate, or peripheral vascular system — the methae'mata blood 
channels of Dr. Marshall Hall (that is, tlie system of vessels 
in which the blood undergoes the change from venous to 
arterial, and conversely). They possess an action distinct 
from that of the heart. 

Ca'ries. (Rottenness.) A disease of bones analogous to ulcer- 
ation of soft tissues ; a term for open ulcer of bone and 
chronic ostitis of its connective tissue, with solution of the 
earthy part. It begins as an inflammation, accompanied by 
periostitis, followed by exudation of new materials and 
softening. Sometimes the bone-cells are filled with a red- 
dish fluid, and there are masses of tubercle. After caries 
has existed for some time the absce.ss bursts ; aperture re- 
mains open, discharging a fluid and particles of bone ; a 
probe is felt to sink into a soft, gritty substance— carious 
bone. Caries is molecular death of bone; necrosis is death 
of a mass of bone. WUlnnl Parker. 

Carotids. The great arteries of the neck, which carry blood 
to the head. 



232 VOCABULARY. 

Caii'tilage. a solid part of the animal body, of a consistence 
between bone and ligament, which in the fetus is a substi- 
tute for bone, but in the adult exists only in the joints, at 
the extremities of the ribs, &c. 

Cer'vical. Everything which concerns the neck, especially 
the back part. 

Chevrotain'. a species of the genus Moschus, related to the 
dser, but having no horns, and otherwise peculiar. It is 
small, light, and graceful, and lives in the mountains of Asia, 
from the Altai to Java. Dana. 

Choroid Membrane. A thin membrane, of a very dark color, 
which lines the sclerotic internally. It is situate between the 
sclerotic and retina, has an opening posteriorly for the pas- 
sage of the optic nerve, and terminates anteriorly at the great 
circumference of the iris, where it is continuous with the cili- 
ary processes. The internal surface is covered with a dark 
pigment, consisting of several layers of pigment cells. Its 
use seems to be to absorb the rays of light after they have 
traversed the retina. 

Cil'iary. Relating to the eyelashes, or to cilia. This epithet 
has also been applied to different parts, which enter into the 
structure of the eye, from the resemblance between some of 
them (the ciliary processes) and the eyelashes. 

Colon. That portion of the large intestines which extends 
from the caecum to the rectum. The colon is usually divided 
into four portions. 1. The right lumbar or ascending colon, 
situate in the right lumbar region, and beginning at the 
csscum. 3. The transverse colon — transverse arch of the 
colon — the portion which crosses from the right to the left 
side, at the upper part of the abdomen. 3. The left lumbar 
or descending colon, extending from the left part of the trans- 
verse arch, opposite the outer portion of the left kidney, to 
the corresponding iliac fossa. 4. The iliac colon, or sigmoid 
flexure of the colon ; the portion which makes a double cur- 
vature in the left iliac fossa, and ends in the rectum. 

In the horse the colon is exceedingly large, and is capable 
of containing no less than twelve gallons of liquid or pulpy 
food. It is of considerable length ; completely traversing the 
diameter of the abdominal cavity, it is then reflected upon 
itself, and retraverses the same space. Touatt. 



THE USES OF COMPARATIVE ANATOMY. 233 

Com'missures. The point of union between two parts; tlma 
the commissures of the eyelids, lips, &c., are the angles which, 
thej form at the place of union. 

Comparative Anat'omy. The science which treats of the 
structure and relation of organs in the various branches of 
the animal kingdom, without a knowledge of which it is im- 
possible to understand the beautifully progressive develop- 
ment of organizaticm, necessary even for tlie full comprehen- 
sion of the uses of many parts of the humaji body, which, 
apparently rudimentary and useless in man, are hio-hly de- 
veloped in other animals. This science is also the basis of 
physiology and the natural classification of animals. 

American Cyclopedia. 

Con'dylb. An articular eminence, round in one direction, flat 
in the other. A kind of process, met with more particularly 
in the ginglymoid joints, such as the condyles of the occipi- 
tal, inferior maxillary bone, &c. 

Conqek'ital (from can and genitus, 'begotten'). Diseases 
which infanta have at birth ; hence, congenital affections are 
those that de])end on faulty conformation, as congenital her- 
nia, congenital cataract, &c. 

CoNJUXCTi'vA Melmbra'na. A mucous membrane, so called 
because it unites the globe of the eye with the eyelids. It 
covers the anterior surface of the eye, the inner surface of the 
eyelids, and the 'caruncula laclirymalis.' It possesses great 
general sensibility, communicated to it by the fifth pair of 
nerves. 

Copyba'ra is the largest known quadruped of the order Ro- 
dcntia, and belongs to the family Cavidss. It is an aquatic 
animal, a native of South America, and feeds on Y^egetable 
food exclusively. Its dentition resembles that of the cavy. 
except that the grinding teeth are formed of many trans- 
verso plates, the number of plates increasing as the animid 
advances in age. It is inoffensive and easily tamed. The 
flesh is esteemed good food. It is somewhat smaller than 
the common hog. Johnson's New Universal Cyclopedia, 

COR'PUSCLE. One of the ultimate morpholoo-ical elements of the 
body. They exist at some time or other in all the tissues of 
the body, g^jverning their vital actions. The white and red 
corpuscles of the blood, epithelial bodies and ganglionic nerve 



234 VOCABULARY. 

cells are examples. Thej are mainly composed of protoplasm 
and contain in their interior bodies called nuclei, in which 
are still smaller ones called nucleoli. T. E. 8atterthwaite. 

Correla'tion (mutual relation) of Forces (otherwise called 
' Transmutation of Force or Energy '). A phrase of recent 
origin, employed to express the theory that any one of the 
various forms of physical force may be converted into one or 
more of the other forms. The cardinal point in this theory 
is the doctrine of heat and its relation to other agents, espe- 
cially to mechanical motion. For example, the heat mani- 
fested when we rub two flat surfaces briskly against each 
other, is only our own muscular motion checked by the fric- 
tion, and changed thereby into the heat which the surfaces 
reveal. On the other hand, this muscular motion is only the 
heat of our bodily frame expending itself in this way. In 
either case the energy has not been annihilated, but only 
transferred, and appears in a new form. 

Johnson's N. JJ. Cyc, article revised hy J. H. Seelye. 

Cruba. The plural of cms, ' a leg.' Applied to some parts of 
the body, from their resemblance to legs or roots, as the 
* crura cerebri,' ' crura cerebelli,' &c. 

Cul-de-sac. Any bag-shaped cavity, tubular vessel, or organ, 
open only at one end. Dana. 



Dental Canal. The bony canals through which the vessels 

and nerves pass to the interior of the teeth. 
Dental Cavity. A cavity in the interior of the teeth, in which 

is situate the dental pulp. (More properly the pulpal cavity.) 
Dental Pulp. The pultaceous substance, of a reddish-gray 

color, very soft and sensible, which fills the cavity of the 

teeth. It is well supplied with capillary vessels. 
Dentig'erous. Tooth-carrying, as dentigerous cysts; one 

containing teeth.- 
Dermal. Relating or belonging to the skin. 
Dermatoid or Dermoid. That which is similar to the skin. 

This name is given to different tissues which resemble the 

skin. The dura mater has been so called by some. 
Deter'gents. Medicines which possess the power to deterge 

or cleanse parts, as wounds, ulcers, &c. 



THE USE OF A DIVERTICULUM. 235 

Diabe'tes. a disease cliaracterized by great augmentation and 
often manifest alteration in the secretion of urine, with ex- 
cessive thirst and progressive emaciation. The quantity of 
urme discharged in 24 hours is sometimes 30 pints and up- 
ward, each pint containing 2] ounces saccharine matter. 

Di'apiiuagm. 1. A dividing membrane or thin partition, com- 
monly with an opening through it. 2. Tlie muscle separa- 
ting the chest or thorax from the abdomen or lower belly ; 
tbe midrifl'. Webstei: 

Diath'esis. Disposition, constitution, affection of the body ; 
predisposition to certain diseases rather than to others. The 
principal diatheses are the cancerous, scrofulous, scorbutic 
(pertoining to scurv\'), rheumatic, gouty, and calculous. 

DiVEiiTic'uiiUM. A blind tube branching out from the course 
of a larger one. An organ which is capable of receiving an 
unusual quantity of blood, when the circulation is obstructed 
or modified elsewhere, is said to act as a diverticulum. 

In the marsupials only four teeth (one in each jaw on each 
side) are deciduous. The permanent set are developed from 
duerticula of the sacs which originated the first set. Gill. 

Dugong'. a herbivorous, cetaceous animal with a tapering body 
ending in a crescent-shaped fin. The fabled mermaid seems 
to have been founded on the dugong. Gilbert. Brande. 

It is generally from 8 to 12 feet long, though it is said to 
sometimes attain the length of 25 feet. The upper lip is 
thick and fleshy and forms a kind of snout ; the upper jaw 
bends downward almost to a right angle ; eyes small, with a 
nictitating membrane ; the skin is thick and smooth. Its 
flesh is said to xesemble beef, and is prized as food. The oil 
is recommended as a substitute for cod -liver oil. J.'s Gye. 

Dura Mater. (Hard.) The outermost of three membranes 
enveloping the brain and spinal cord. Within the skull 
it so completely joins the bones that it may be regarded 
as th^ir endosteum. Within the spinal canal it becomes 
a fibrous tube, separated from the vertebrae (which have 
no endosteum) by a loose, areolar, fatty tissue and a plexus 
of veins. It sends out sheaths for the nerves as they go 
through their foramina. It is usually studded, except in 
infancy, b/minute whitish masses (Paccionian bodies) whose 
use is not known. Its inner surface is covered with pave- 



236 VOCABULARY. 

ment epithelium, and perhaps by the parietal layer of the 
arachnoid membrane. 1 b r\ 

E. 

Econ'omy. By the term 'animal economy' is understood the 
aggregate of the laws which govern the organism. The word, 
economy is also used for the aggregate of par^s which con- 
stitute man or animals. 

Edenta'ta. In natural history, an order of animals that are 
destitute of front teeth, as the armadillo and ant-eater. Bdl. 

Eden'tulus. One Avithout teeth. 

Em'bryo. The fecundated germ, in the early stages of its de- 
valopmant in utero. At a certain period of its increase, the 
name 'fetus' is given to it, but at what period is not deter- 
mined. Generally, the embryo state is considered to extend 
to the perioJ of quickening. 

Encephali'tis. This term has been used by some nosologists 
(classiiiers of diseases) synonymously with ' cephalitis ' and 
'phranitis.' By others it has been appropriated to inliam- 
mation of the brain, in contradistinction to that of the meai- 
branes. 

E'ocbne. In geology, a term applied to the earlier tertiary de- 
posits, in which are a few organic remains of existing species 
of animals. Hence the term eocene (recent), which denotes 
the dawn of the existing state of things. 

Dana. Lyell. Mantell. 
In America the eocene strata contain numerous fossils, 
mostly marine moUusks, but also include some gigantic ver- 
tebrates, a carnivorous cetacean seventy feet in length, and a 
shark of which the teeth are sometimes six inches in length. 
The Wyoming beds have furnished the remains of a remark- 
able group of mammals, which are thought by Prof. Marsh 
to form a new order, and which he has named ' Dinocerata.' 
The largest of these (Dinoceras mirabilis) had the bulk of an 
elephant, and was provided with three pairs of horns and a 
pair of great saber-like canine teeth. Johnson's JST. U. Cyc. 

Epider'mis. a modification of the epithelium, molded to th.e 
papillary layer of the true skin ; composed of agglutinated, 
flattened cells, which are developed in the liquor sanguinis, 
the latter being poured out on the true skin's external sur- 
face. In the deeper layers the cells are rounded or columnar. 



THE UNIVERSE A SERIES OF CHANGES. 237 

containing- in most races of men more or less pigmentary 
matter, wliicli gives the skin its various shades from black 
to white. It is penetrated by the ducts of the skin's sweat- 
glands and oil-glands ; becomes hard in palms of hands; 
otherwise is soft. The hair and nails are modifications of it. 
On leaves it is penetrated by the stomata, transmitting 
exhalations and absorbing carbonic acid, the most important 
part of plant food. Ibid. 

Epithelium. (Soft, delicate, tender.) The layer of cells lin- 
ing serous (closed) and mucous (open) cavities, the mucous 
epithelium being continuous with the epidermis. (Mucous 
is formed by the bursting of epithelial cells.) Ihid. 

Esoph'agus. The gullet. Extends from pharynx to stomach. 
Ethmoid. Sieve-like. The ethmoid hone is one of the eight 
bones which compose the cranium, so called because its up- 
per plate is pierced by numerous holes. It is situate at the 
anterior, inferior, and middle part of the cranium. 
Evolu'tion. According to the hypothesis of evolution, in its 
simplest form, the universe as it now exists is the result of 
"an immense series of changes," related to and dependent 
upon each oiuer, as successive steps, or rather growths, con- 
. stituting a progress ; analogous to the unfolding or evolving 
of the parts of a living organism. Evolution is defined by 
Herbert Spencer as consisting In a progress from the homo- 
geneous to the heterogeneous, from general to special, from 
the simple to the complex ; and this process is considered to 
be traceable in the formation of the worlds in space, in the 
multiplication of the types and species of plants and animals 
on the globe, in the origination and diversity of languages, 
literature, arts, and sciences, and in all the changes of human 
institutions and society. Henry Hartshorne. 

The animal kinffdora displays a unity of plan or a correla- 
tion of parts by which common princir-les are traced through 
the most disguising diversities of form, so that in nspect, struc- 
ture, and functions the various tribes of animals pnss into 
each other by sTifrht and gradual transitions. The arm of a 
man, the fore limb of a qnodnmed, tho wing of a bird, and 
the fin of a fish are homologous, that is, they contain the 
same essential parts, modified in correspondence with thf dif- 
ferent circumstances of the animal ; and so with the other 



238 VOCABULARY. 

orgr.ns. Prof. Cope says : " Every individual of every species 
ox a giveu branch of tiie animal king-dom is composed of ele- 
ments common to all, and the dilTvirijaces whicli are so radi- 
cal in the higher grades are but the modifications of the same 
elemental parts." E. L. Toumans. 

Exfolia'tion (from ex ^n^i folium, ' a leaf). By this is meant 
the separation of the dead portions of a bone, tendon, apon- 
eurosis (a white shining membrane), or cartilage, under the 
form of lamellae (small scales). Exfoliation is accomplished 
by the instinctive action of the parts, and its object is to de- 
tach the dead portions from those subjacent, which are still 
alive. For this purpose the latter throw out fleshy granula- 
tions, and a more or less abundant suppuration occurs, which 
tends to separate the exfoliated part — now become an extra- 
neous body. 

ExosTo'sis. An osseous tumor, which forms at the surface of 
bones, or in their cavities. 

Exostosis Deis^tium. Exostosis of the teeth. 

F. 

Ferru'ginous (chalyb'eate). Of or belonging to iron ; contain- 
ing iron. Any medicine into which iron enters, as chalyb- 
eate mixture, pills, waters, &c. 

Fe'tus. Si^e ' embryo.' 

Fiber. An organic filament, of a solid consistence, and more or 
less extensible, which enters into the composition of every 
animal and vegetable texture. 

Fil'ament. A tliread. This word is used synonymously with 
fibril ; thus we say a nervous or cellular filament or fibril. 

Fis^TULA. ' A pipe or reed.' A solution of continuity (a division 
of parts previously continuous) of greater or less depth and 
sinuosity, the opening* of which is narrow, and the disease 
kept up by an altered texture of parts, so that it is not dis- 
posed to heal. A fistula is ' incomplete ' or ' blind' when it 
has but one opening, and ' complete ' when tltere are two, the 
one comrauniciting with an internal cavity, the other exter- 
nally. Ir is lined in its whole course by a membrane which 
seems analogous to mucous membranes. 

Fol'licle. a follicle or crypt is a small, roundish, hollow 
bodv, situate in the substance of the skin or mucous mem- 
branes, and constantly pouring the fluid which it secretes on 



USES OF GASTRIC JUICE. 239 

their surfacc^s. Tlie use of tLe secretion is to keep tlic parts 
on wiiicli it is poured supple and moist, and to preserve tlieiu 
from, the action of irritating bodies with which they have to 
come in contact. 

Foka'mkn. Any cavity pierced tLrough and through. Also 
tho orifico to a canal. 

Fossa. A cavity of greater or less depth, the entrance to which 
is al ways larger than the base. 

Fr^num. a small bridle. A name given to several membran- 
ous folds, which bridle and retain certain organs. 

Frontal Bone. A double bone in the fetus, single in the adult, 
situate at the base of the cranium, and at the superior part 
of the face. 

Function. The action of an organ or system of organs. Any 
act necessary for accomplishing a vital phenomenon. A 
function is a special office in the animal economy, which has 
as its instrumeut an organ or apparatus of organs. 

Fungus. The mushroom order of plants. In pathology the 
word is commonly used synonymously with fungosity (my- 
cosis). 

Fungus H^mato'des (Hsematodes Fungus). An exceedingly 
alanning carcinomatous (cancerous) affection, which was first 
described with accuracy by Mr. John Bums, of Glasgow. It 
consists in the development of cancerous tumors, in which 
the inflammation is accompanied with violent heat and pain, 
and with fungus and bleeding excrescences. 

G. 

Gang'lion. Nervous ganglions are enlargements or knots in 
the course of a nerve. 

Gastric. Belonging or relating to the stomach. 

Gastric Juice. A fluid secreted from the nmcons membrane 
of the stomach. It assists digestion. 

Gentian Wine (vinnm gentianae compositnm, or wine bitters). 
'Gentiana Lutea' is the systematic name of the officinal 
gentian. The plant is common in tlie mountains of Europe. 
The root is almost inodorous, extremely bitter, and yields 
its virtues to ether, alcohol, and water. It is tonic and 
stomachic, afnd, in large doses, aperient. It is most fre- 
quently, however, used in infusion or tinctme. 



240 VOCABULARY. 

Geol'ogy is that brancli of natural science whicli treats of tlie 
structure of the crust of the earth aud the mode of formation 
of its rocks, together with the history of physical changes 
and of life on our planet during the successive stages of its 
history. It has been inferred that its actual crust must be 
very thick, perhaps not less than 2,500 miles. Geology de- 
pends upon mineralogy for its knowledge of tlis constituents 
of rocks, and upon chemistry and j)hysics for its knowledge 
of the laws of change ; aud in its study of fossil remains it is 
closely connected with the sciences of zoology and botany. 
A knowledge of geology lies at the base of physical geogra- 
phy, aud is essential to the skillful prosecution of mining 
and other useful arts, J. W. Bawsoji. 

The facts proved by geology are that during an immense 
but unknown period the surface of the earth has undergone 
successive changes ; land has sunk beneath the ocean, while 
fresh land has risen up from it ; mountain chains have been 
elevated ; islands have been formed into continents, and con- 
tinents submerged till they have become islands ; and these 
changes have taken place, not once merely, but perhaps 
hundreds, perhaps thousands of times. A. L. Wallace. 

Prof. Dana says the " earth was first a featureless globe of 
fire ; then had its oceans and dry land ; in course of time re- 
ceived mountains and rivers, and finally all those diversities 
of surface which now characterize it," 

Gland. (An acorn ; a kernel.) Softish, granular, lobated or- 
gans, composed of vessels and a particular texture, which 
draw from the blood the molecules necessary for the forma- 
tion of new fluids, conveying them externally by means of 
one or more excretory ducts. Each gland has an organiza- 
tion peculiar to it, but we know not the intimate nature of 
the glandular texture. 

Guana'co. The ' Auchenia Huanaca,' a species of the genus of 
ruminant mammals to which the llama belongs. It inhabits 
the Andes, and is domesticated. Ii is allied to the camel. 

Webster. 

The guanaco is especially abundant in Patagonia and 

Chili, where it forms largo flocks. It is about three feet high 

at the shoulders, and is extremely swift. In domestication it 

is ill-tempered, and has a disagreeable habit of ejecting saliva 



HISTOLOGY— nUMAX, COMPARATIVE, ETC. 2-41 

upon unwelcome visitors. In its wild state it seldom drinks 
water. Its flesh is edible and its skin valuable. 

Johnson's N. U. Cyc- 
H. 

Haversian Canals. (Canals of Havers, nutritive canals, &c.) 
The canals throug'h which the vessels pass to the bones. 
They are lined by a very fine lamina of compact texture, or 
are formed in the texture itself. There is generally one large 
nutritious canal in a long bone, situate toward its middle. 

Hia'tus. a foramen or aperture. Mouth. The vulva. Also 
yawning. 

Htstol'ogy is the branch of anatomy which treats of the minute 
structure of the tissues of which living beings arc composed. 
It is divided into ' human histology,' which treats of the tis- 
sues of man ; ' comparative histology,' which treats of the tis- 
sues of the lower animals, and ' vegetable histology,' which 
treats of the tissues of plants. Each of these divisions may 
be subdivided into 'normal' and 'pathological' histology, 
the first referring to the healthy tissues, the second investi- 
gating the changes they undergo in disease. J. J. Woodward. 

Hoove. A disease in cattle, consisting in the excessive inflation 
of the stomach by gas, ordinarily caused by eating too much 
green food. Gardner. 

Hyper'trophy. The state of a part in which the nutrition is 
performed with greater activity, and which on that account 
at length acquires unusual bulk. The part thus aflFected is 
said to be hypertrophied or hypertrophous. 

I. 

Infiltra'tion. To filter ; eff'usiou. The accumulation of a 
fluid in the areolae of a texture, and particularly in the areo- 
lar membrane. The fluid eff'ussd is ordinarily the * liquor 
sanguinis,' sound or altered ; sometimes blood or pus, faeces 
or urine. When infiltration of a serous tluid is general, it 
constitutes 'anasarca' (dropsy) ; when local, ' oedema.' 

Intersti'tial. Applied to tliat which occurs in the interstices 
of an organ, as interstitial absorption, interstitial pregnancy, 
&c. (See ' Suppuration.') 

Intra-uterixe. ' {Tntra, 'within,' uterus, 'the womb.') That 
which takes place within the womb, as intra-uterine life. 
11 



24:2 VOCABULARY. 

Ikis. So called from its reseiuVin^ tlie rainbow in a, variety of 
colors. A membrane, stretclied vertically at the anterior 
part Of the eye, in tlie midst of tlie aqueous humor, in which 
it forms a Idni of circular, flat par Li Lion, separating the an- 
terior from the posterior chamber. It is perforated by a cir- 
cular opening called the pupil, which is constantly varying 
its dimensions, owing to the contractions of the fibers of the 
iris. 

Isodac'tyle. Hoofed quadrupeds with toes in even number, as 
two or four, and which have a more or less complicated 
stomach, with a moderate-sized, simple caecum. Examples: 
Ox, hog, peccary, hippopotamus. li. Owen. 

Lach'rymal. Belonging to the tears. This epithet is given 
to various parts. 

Lacuna op Bone. Certain dark, stellate spots, with thread- 
like lines raliating from them, seen under a high magnifying 
power. These were first believed to be solid csseous cor- 
puscles or cells (corpuscles of Purkinje), but are now re- 
garded as excavations in the bone, with minute tubes or 
canalic'uli proceeding' from them and communicating with 
the Haversian canals. The lacunse and canaliculi are fibers 
concentrated in the transit of nutrient fluid through the osse- 
ous tissue. 

Lam'ina. "A thin, flat part of a bone; a plate or table, as the 
cribriform lamina or plate of the ethmoid bone. Lamina and 
lamella are generally used synonymously, although the latter 
is properly a diminutive of the former. 

Lesio :. Darangemant, djsorder; any morbid change, either in 
the exercise of functions or in the texture of organs. ' Or- 
ganic lesion ' is synonymous with organic disease. 

Lipo'ma. a fatty tumor of an encysted or other character. 

Lipom'atous. Having the nature of lipoma, as a lipomatous 
mass. 

Liquor S-VJMg'uinis. A term given by Dr. B. Babington to one 
of the constituents of the blood, the other being the red par- 
ticles. It is the effused material (called plasma, coagulable 
or plastic lymph, intercellular fluid, &c.), from which the cells 
obtain the constituents of the diflbrent tissues and secretions. 



M0LAr..3 WITH co:>E-LiKE n:ojECTioxs. 243 



M. 

Malar. Belonfrin^ to the clieek, as the malar bone. 

MAiiAR Process. Zygomatic process. (Cheek bone process.) 

Masseter. a muscle situate at the posterior part of the cheek, 
and lying u!)on the ramus ot t!ie lower jawbone. Its otfice is 
to raise the lower jaw and to act in mastication. 

Mas'todon. An extinct genus of quadrupeds. When alive it 
must have been twelve or thirteen feet lii<?h, and, including 
the tusks, a'oout twenty-five feet long. Tue tusks measure 
ten feet eleven inches, about two and a Imlf feet being im- 
planted in the socket. According to Owen, the teeth are 
seven on each side, above and below. The molars have 
wedge-shaped, transverse ridges, the sumnnits of which are 
divided by a depression lengthwis3 with the tooth, and sub- 
divided into cones, more or less resembling the teats of a cow. 
In some species there are from three to five ridp:es to each 
posterior molar; in other species five or more. 0. G. Marsh. 
(The mastod )n takes its name from the mastoid or nipple- 
like processes of its teeth.) 

Mastoid. Having the form of a nipple. 

Max'illary. Relating or belonging to the jaws. 

Mea'tos. a passage or canal. 

Median Line. A vertical line, supposed to divide a body lon- 
gitudinally into two equal parts, the one right, the other left. 

Med'ullary. Relating to the marrow, or analogous to marrow. 

Megathe'riu.m. An extinct genus of Quaternary mammals. 
' Megatherium Cuvieri/ from South America, exceeded the 
rhinoceros in size, its skeleton measuring eighteen feet in 
length. The vertebrae of tlie tail are very large and power- 
ful, and that organ, with the hind-legs, seems to have formed 
a support for the heavy body, while th? huge fore-legs were 
employed in breaking the branches from trees or tearing 
them down for food. There are four toes in front and two 
behind. The teeth, five above and four below on each side, 
resemble those of the sloths. They grew from persistent 
pulps, and are deeply implanted in the jaws ; they have a 
grinding surface of triangular ridges, and were fitted for mas- 
ticating coarse vegetal)le food. 0. C. Marsh. 

Membrane. A name given to different thin organs, represent- 



244 VOCABULARY. 

ing a spscies of supple and more or less elastic webs, varying 
in tlieir structure and vital properties, and int3nded, in gen- 
eral, to absorb or secrete certain fluids, and to separate, en- 
velop, and form other organs. Bicliat has divided the mem- 
branes into simple and compound. 

Membra'na Nic'titans. The ' haw' of the horse's eye. It is 
a triangular-shaped cartilage, concealed within the inner cor- 
ner of the eye, and is black or pied. It is used by the horse, 
in lieu of hands, to wipe away dust, insects, &c. The eye 
of t'he horse has .strong muscleis. attached to it, and one, 
peculiar to qtiadriipeds, by the aid of which the eye may be 
drawn back out of the reach of danger. When this muscle 
acts, the haw, which is guided by tiie eyelids, shoots across 
the eye with the rapidity of lightning, and thus carries off 
the offending matter. Its return is equally rapid. Youatt. 
(Prof. Youatt denounces the practice of cutting out the 
haw as barbarous, that is, in ordinary cases of infllaramation. 
He says that if farriers and grooms were compelled to walk 
for miles in the dust without being permitted to wipe or 
cleanse their eyes, they would feel the torture to which they 
often subject the horse.) 

Mi'ocENE. Literally, less recant. In geology, a term applied 
to the middle division of the tertiary strata, containing fewer 
shells of recent species than the Pliocene, but more than the 
Eocene. Lyell. 

The Miocene is apparently the culminating age of the 
mammalia, so far as physical development is concerned, 
which accords with its remarkably genial climate and exu- 
berant vegetation. In Europe the beds of this age present 
for the first time examples of the monkeys. Among carniv- 
orous animals, we have cat-like creatures, one of which is dis- 
tinguished from all modern animals of its group by the long, 
saber-shaped canines of its upper jav% fitting it to pull down 
and destroy those large pachyderms whicl) could have easily 
shaken off a lion or a tiger. Here also we have the elephants, 
the mastodon, a great, coarsely-built, hog-like elephant, 
some species of which had tusks both in the upper and lower 
jaw ; the rhinoceros, the hippopotamus, and the horse, all of 
extinct species. J- W- Dairson. 

Morpholog'ical. That which has relation to the anatomical 



THE USES OF MOKPHOI.OGY. 245 

conformation of |)arts. Applied at times to the alterations 
in the ' form ' of the several parts of the embryo, in contra- 
distinction to ' histological,' which is applied to the transfor- 
mation by which the tissues are gradually generated. In 
comparative anatomy it is applieJ to the history of the modi- 
fications of forms which the same organ undergoes in differ- 
ent animals. 

Morphol'ogy is that branch of zoology, in its widest sense, 
whicii treats of the general form (not outline) and organiza- 
tion of animals, and the principles involved, as well as the 
correspondence in the various forms of the several members 
and parts, so far as they are comparable in any structural 
characters, but entirely independent of the uses of the parts 
and organs. It thus contrasts witli animal physiology, which 
treats of the organization in whol.', so far as respects adapta- 
tion to surroundings, as well as the various parts and organs, 
so far as their uses and functions are concerned. To discover 
the utility of organization in diverse animal forms and the 
essential similarity in their mode of evolution, are the prin- 
cipal problems within the province of morphology. Gill. 

Mucous Membrane (liliing of alimentary, respiratory, and 
genito-urinary tracts) consists of mucous membrane proper 
and submucous tissues. The first consists of secretory tuber- 
cles, follicles, and glands ; the second of elastic connective 
tissue (capillary blood-vessels and nerve-iilanieuts) by which 
the secretory surface is nourished. Its free surface is lined 
with epithelial cells, related to the mucous tissues beneath as 
the epidermic cells are to the skin ; affords an extensive sur- 
face for the great functional glandular processes of nutritive 
absorption and the elimination of effete excretory products. 
Its special function is to secrete mrtcus, and thus protect its 
passages from the contact, attrition, and irritation of their 
moving contents. ^Mucus consists of water, mucosine, and 
salts. When rich in mucosine, it is viscid and tenacious ; 
when salines predominate, it is scarcely more than transuded 
blood-serum. K 1). Hfichon, Jr. 

Musk-Deee. a small deer of Central Asia ; a timid creature of 
nocturnal habits, and is much hunted for its yield of musk, 
which is obtained from a sac beneath the abdomen, on the 
male alone. The flesh is esteemed, though that of the male 



246 VOCABULARY. 

is very rank and somewhat musky. It ranges from Siberia 
to Tonquin. Johns Jii's N. U. Cyc. 

MuNTJAC, of India, Java, &c. , a small deer, but little over two 
feet liigli. Tiie males have small iiorns ; the females are 
hornless. Tiieir flesh is excellent. The Chinese muntjac, 
like the preceding-, is often half domesticated, and is some 
times bred in European parks. Johnson's i\. U. Cyc. 

Myl'odon. An extinct edentate animal, allied to the megathe 
rium. Lyell 

IS. 

Nar'whal, or Sea-Untcorn. It is most nearly related to the 
white whale. Belonging to an order in which many of the 
members never develop teath at all, it, of all animals, is sup- 
plied with a tooth altogether out of proportion to its size, and 
it is, moreover, developed in utter contravention of the rules 
of bi lateral symmetry, which in every known case among 
. vertebrates govern the production of the teeth. In both 
sexes the lower jaw is edentulous. The male, however, is 
provided, on the left side of the upper jaw, with a tusk from 
eight to ten feet long. It is straight, spirally grooved ex- 
ternally, and hollowed within into a persistent pulp-cavity. 
On the right side the corresponding tooth generally remains 
hidden, smooth, and solid, within the jaw. In addition to 
these, there are two small rudimentary molars concealed in 
the upper jaw. The narwhal, which is considered one of 
the greatest curiosities of natural history, attains to a length 
of fifteen feet. Its single spiracle or blow-hole is situated on 
the top of the head. E. G. H. Day. 

Necro'sis. or death of a bone, corresponds to mortification of 
the soft structures, and is as distinct from caries as mortifica- 
tion is from ulceration. Necrosis is divided into four varie- 
ties, namely: 1. The scrofulous. 2. The superficial, or that 
which involves the outer lamellae, and presents itself in the 
flat and long- bones, 3. That form which destroys the in- 
ternal part of a bone, and in which the outer shell is not af- 
fected. 4. That in which the whole thickness of the bone 
dies. W. Williams. 

O. 

Odontal'gia. Toothache, 

Odontog'eny. Generation or mode of development of the teeth. 



A DUCK-BILLED MAMMAL. 247 

OdontoCt'raphy. a description of the teeth. 

Odon'toid. Tooth-shaped. 

Odontol'ithos. a sort of incrustation, of a yellowish color, 
which forms at the coronae of the teeth, and is called ' tartar.' 
It consists of 79 parts of phosphate of lime, 13i of mucus, 1 
of a particular balivary matter, and 7i of animal substance, 
soluble hi chlorohydric acid. A species of infusoria, * deutic- 
ola hominis/ has been found in it. 

Odontolt'ogy. An anatomical troatiso of the teeth. 

Oral. Relating to the mourn or to speech. 

Oral Epithe'lium. See 'Epithelium.' 

ORNiTnoTinYN'cHUS. An effodieut (diggiuof), monotrematous 
mammal, with a horny beak resembling that of a duck, and 
two merely fibrous cheek teeth on each side of both jaws, not 
fixed in any bone, but only in the o-um ; with pentadactylous 
(fivo-fing(Ted) ]iaws, webbed like the feet of a bird, and 
formed for swimming, and with a spur in the hinder feet, 
emitting- a poisonous liquid from a reservoir in the sole of the 
foot, supplied by a gland situated above the pelvis, and by 
the side of the spine. The animal is covered wdth a brown 
fur. It is found only in New Holland, and is sometimes 
called Water Mole. Bell. 

As the name of the order imports, the alimentary, urinary, 
and reproductive organs open into a common cloaca, as in 
birds ; mammary glands arc present, secreting milk for the 
young, which are born blind and naked ; there are no prom- 
inent nipples, and the mammary openings are contained in 
slits in the integument ; M. Verreaux says the young, when 
they are able to swim, suck in the milk from the surface of 
the water, into which it is emittecl. Americin Cyc. 

'Duck-Bill,' the English name of the Ornithorhynchus par- 
adoxus, found in Van Diemen's land and Australia. In its 
bill-like jaws, its spurs, its monotrematous character, its non- 
placental development, and its anatomy, it appears to be a 
connecting link between birds and mammals. The Duck-Bill 
is the only animal of its genus. It is about fifteen inches 
long ; it climbs trees with facility, and digs burrows, often 
thirty feet long, in the river bank, with one opening above 
and another below water. It inhabits ponds and quiet 
streams, swimming about with its head somewhat elevated, 



248 VOCABULARY. 

often diving for its food, wliicli consists of insects and other 
small aquatic animals. Johnson's N. U. Cyc. 

Of all the mammalia yet known, the Ornithorhynchus 
seems the most extraordinary in its conformation, exhibiting 
the perfect resemblance of the beak of a duck engrafted on 
the head of a quadruped. Dr. Shaw. 

Accordini? to Ernst H. Haeckel, these animals " are be- 
coming less numerous year by year, and will soon be classed, 
with all their blood relations, among the extinct animals of 
ouv globe. " 

Os. A bone ; also a mouth. 

Osteol'ogy. The part of anatomy which treats of bones. 

Osteo-sarco'ma. Disease of the bony tissue, which consists in 
softening of its laminge, and ^heir transformation into a fleshy 
substanca, analogous to that of cancer, accompanied with 
general symptoms of cancerous affbction. The word has also 
often been used synonymously with 'spina ventosa.' 

O'v ARIES {ovum, egg). The two organs in oviparous animals 
in which the ova, the generative product of the female, are 
formed. They are termed b}'- Galen * testes muliebres,' since 
they are in women the analogues of the testes in men. The 
ovaries in adult women are situated on either side of the 
uterus, in the iliac fossae ; they are included in the two pel- 
vic duplicatures of the peritoneum, which are called the 
broad ligaments. Each ovary is also attached by a round, 
fibrous cor J — the ovarian ligament — to the side of the uterus, 
and by a lesser fibrous cord to the fringed edge of the Fallo- 
pian oviduct. The ovary is an oblong, ovoid, flattened body, 
of a whitish color and uneven surface. It is ^ to |^ an inch 
thick, f of an inch wide, and 1 inch to 1|- long; it weighs 
from 1 to 2 drachms. M Darwin Hudson, Jr. 

Oze'na. An affection of the pituitary membrane, which gives 
occasion to a disagreeable odor similar to a crushed bed-bug. 
P. 

Paleontol'ogt. The study of ancient beings. The science 
which treats of the evidences of organic life upon the earth 
during the different x^ast geological periods of its history. 
These evidences consist in the remains of plants and animals 
imbedded or otherwise preserved in the rocky strata or upon 
their surfaces, and in other indications of animal existence, 



FOOTPIilXTS IN THE SAXDS OF TIME. 2-19 

such as trails, footprints, burrows, and coprolitic or other 
organic material found in the rocks. Pythagoras, Plato, 
Aristotle, and other ancients, allude to the existence of ma- 
rine sliells at a distance from the sea : it was cimsidered con- 
clusive evidence that the rocks containing them had formerly 
been submero-ed beneath the ocean. A7n. Cyc. 

Papil'la. The end of the nipple, or an eminence similar to a 
nipple. 

Tlie minute elevations of the surface of the skin, tongue, 
&c. They serv<i to increase the extent of surface for vascular 
distribution, or subserve sensitive or mechanical purposes. 
Some contain one or more vascular loops ; others, nervous 
elements. Some are surmounted by dense epithelial fila- 
ments, as those which give the roughness to the tongue. 

Par'asite. Parasites are plants which attach themselves to 
other plants, and animals which live in or on the bodies of 
other animals, so as to subsist at their expense. The mis- 
tletoe is a parasitic plant, the louse a parasitic animal. 
Pari'etes. a name given to parts which form the inclosure or 
limits of different cavities of the body, as the parietes of the 
cranium, chest, &c. 
Parot'id. ('About the ear.') The largest of the salivary 
glands, seated under the ear and near the angle of the lower 
jaw. It secretes saliva. 
Pathol'ogy. The branch of medicine whose object is the 
knowledge of diseas-. It has been defined ' diseased physiol- 
ogy,' and ' physiology of disease.' It is divided into general 
and special. The first considers diseases in common ; the 
second the particular history of each. It is subdivided into 
internal and external, or medical and surgical. 
Pelvis The part of the trunk which bounds the abdomen 

below. 
Periodonti'tis. Inflammation of the membrane that lines the 

socket of a tooth. 
Per'Os'teum. The periosteum is a fibrous, white, rerastin^ 
medium, which surrounds the bones everywhere, except the 
teeth at their coronre (crowns), and the parts (jf other bones 
that are cc^vered with cartilage. The external surface is 
united, in a more or less intimate manner, to the adjoining 



250 yOCABULAKY. 

parts by areolar tissue. Its inner surface covers the bones, 
whose depressions it accurately follows. It is united to the 
bone by small fibrous prolongations, and especially by a pro- 
digious quantity of vessels, which penetrate their substance. 
It unites the bones to the neighboring parts, and assists in 
their growth, either by furnishing, at its inner surface, an 
albuminous exudation, which becomes cartilaginous and at 
length ossifies, or by supporting the vessels which penetrate 
them to carry the materials of their nutrition. 

Petrous. Resembling stone ; having the hardness of stone. 

Phlegmon. Inflammation of the areolar texture, accompanied 
with redness, circumscribed swelling, increased heat and 
pain, which, at first, is tensive and lancinating and afterward 
pulsatory and heavy. It is apt to terminate in suppuration. 

PiA Mater (tender mother), so named because it nourishes the 
nerve-centers. The innermost covering of the brain and 
spinal cord ; a fine plexus of blood-vessels, dipping into the 
brain's convolutions, forming the velum interpositum in the 
third and the choroid plexus in the fourth ventricle. A 
small part (over the crura and pons) is not very vascular, but 
tough and fibrous, while that of the spinal cord, with which 
it is intimately connected and of which it is the neurilemma, 
is still less vascular. It is partly composed of longitudinal 
fibrous bundles, and is abundantly supplied with nerves and 
lymphatics. The tunica vasculosa of the testes is also called 
pia mater. Johnson's N. U. Cyc. 

PiTU'lTARY. Concerned in the secretion of muscus or phlegm. 

Pituitary Membrane. The mucous membrane which lines 
the nasal fossae, and extends to the cavities communicating 
with the nose. It is the seat of smell. 

Plas'ma. See * Liquor Sanguinis.' 

Pleistocene. A term used to denote the newest tertiary de- 
posits. Johnson's JSf. JJ. Cyc. 

Pli'ocene. In geology, the term applied to the most modern 
of tertiary deposits, in which most of the fossil shells are of 
recent species. Lyell. 

With regard to animal life, the Pliocene continues the con- 
ditions of the Miocene, but Avith signs of decadence. The 
Pliocene was terminated by the cold or Glacial period, iu 
which a remarkable lowering of temperature occurred over 



THE WOOLLY HIIIX()CE11;)S; 251 

all the northern hemisphere, ace )mpauieJ, at least in a por- 
tion of the time, by. a very general and great sabsideiice, 
which laid all the lower part of our continent under water. 
This terminated much of the life of the Pliocene, and re- 
placed it with boreal and arCtic forms, some of them, like the 
great hairy Sibe ian mammoth and the woolly rhinoceros, lit 
succassors of tlie gijautic Miocene fauna. J. W. Dawson. 

PoL^rPus. A name given tj tumors which occur in mucous 
membranes especially, and which have been compared to cer- 
taiu zoiiphytes. Polypi may form on every mucous mem- 
brane. They vary much in size, number, mode of adhesion, 
and in:;imate nature. Fibrous polypi are of a dense, compact 
texture and whitish color. They contain few vessels and do 
not degenerate into cancer. The scirrhous or carcinomatous 
are true cancerous tumors, painful and bleeding. 

Pons Varolii. An eminence at the upper part of the medulla 
oblongata, first described by Varolius. It is formed by the 
union of the crura cerebri and crura cerebelli. 

PosTu'moR. Opposed to ' anterior,' which see. 

Pteii'ygoid. a name g-iven to two processes at the inferior 
surface of the sphenoid bone, the two laminae which form 
them having bean compared to wings. 

Pylor'ic. That which relates to the ' pylorus.' An epithet 
given to differant parts. 

Pylo'rus. a 'gate,' a 'guardian.' The lower or right orifice 
of the stomach is called 'pylorus' because it closes the en- 
trance into the intestinal canal, and is furnished with a cir- 
cular, flattened, fibro-mucous ring, which causes the total 
closure of the stomach during digestion in that organ. It is a 
fold of the mucous and muscular membranes of the stomach, 
and is the ' pyloric muscle' of some authors. 

Q. 

Quadruma'na. (Qitatuor, ' four,' and manus, ' hand.') A name 
employed by Bluraenbach (in 1791) as an ordinal designation 
for the monkeys, lemurs, and related types, man having 
been isolated as the representative of a peculiar orv'.cr named 
Bi manus. The views thus expressed were for a long time 
prL^doniinant ; but a closer study of the structure of the forms 
indicated bf those names has convinced almost all living 
naturalists that tliey were erroneously separated, and the two 



26:4^ , VOCABULAKY. 

types are now generally combined in one order named Pri- 
mates, under which head man and the monkeys are com- 
bined together in one sub-order (Anthropoidea), and con- 
trasted with the lemurs, which constitute another sub-order 
(Prosimiae). Theodore Oill. 

K. 

Rectum. The third and last portion of the great intestine. It 
forms the continuation of the sigmoid flexure of the colon, 
occupies the posterior part of the pelvis, and extends from 
the sacro- vertebral articulation to the coccyx (rump or crup- 
per bone), before which it opens outward by the orifice called 
the 'anus.' 

Reg'ime. Mode of livinpj; government, administration. 

Reg'imen. The rational and methodical use of food and of 
everything essential to life, both in a state of health and dis- 
ease. It is often restricted in its meaning to ' diet.' It is 
sometimes used synonymously with hygiene (health). 

Ru'minant. a division of animals having four stomachs, the 
first so situated as to receive a large quantity of vegetable 
matter coarsely bruised by a first mastication, which passes 
into the second, where it is moistened and formed into little 
pellets ; these the animal has the power of bringing again to 
the mouth, to be rechewed, after which it is swallowed into 
the third stomach, from which it passes into the fourth, 
where it is finally digested. Webster. 

(Several vv'ell authenticated cases of human beings who 
ruminated their food are on record.) 
S. 

Sarco'ma. Any species of excrescence having a fleshy consist- 
ence. 

SCHNEIDERIAN MEMBRANE. See * Pituitary membrane.' 

Sclerot'ic. a heavy, resisting, opaque membrane, of a pearly 
white color and fibrous nature, which covers nearly the pos- 
terior four-fifths of the globe of the eye, and has the form of 
a sphere truncated before. 

Sella Tur'cica. (Turkish saddle.) A depression at the upper 
surface of the sphenoid bone, which is bounded, anteriorly 
and posteriorly, by the clinoid processes, and lodges the pitu- 
itary gland. It is so called from its resemblance to a Turkish 
saddle. 



THE IIOllSi:, ASS, MULE, QrAGGA. 25;> 

Septum. A part intended to separate two cavities from each 
other, or to divide a principal cavity into several secondary 
cavities. 

Skrous. Thin, watery. Kelating to tbe most watery portion 
of animal tiuids, or to membranes that secrete them. 

Sol'iped. An animal whose hoof is not cloven ; one of a group 

of animals with nndivided hoofs; a solid nngnlate. Webster. 

The family ' Solipoda' consists of several species of horse, 

namely, the ass, the mule, and the quagga. Youatt. 

Sphenoid. Wedge-shaped. 

Sphenoid Bone. An azygous (single) bone, situate on the me- 
dian line, at the base of the cranium. It articulates with all 
the bones of that cavity, supporting them and strengthening 
their union. Its form is singular, resembling a bat witli its 
wings extended. 

Spina Vento'sa. See ' Osteo-sarcoma.' 

Styloid. (A style, a peg, a pin.) Shaped like a peg or pin. 

Sdbmax'illary (from suh, 'under,' maxilla, 'the jaw'). That 
which is seated beneath the jaw. 

Suppuka'tion. Formation or secretion of pus. It is a frequent 
termination of inflainmation, and may occur in almost any of 
the tissues. This termination is announced by slight chills, 
by remission of the pain, which, from being lancinating, be- 
comes heavy ; by a sense of weight in the part, and, when 
the collection of pus can be easily felt, by fluctuation. When 
pus is thus formed in the areolar membrane, and is collected 
in one or more cavities, it constitutes an 'abscess,' If it be 
formed from a surface exposed to the air, it is an ' ulcer.' and 
such ulcers we are in the habit of establishing artificially in 
certain cases of disease. 

Supra. A common Latin prefix, signifying 'above.' 

Suture. A kind of immovable articulation, in which the bones 
unite by means of serrated edges, which are, as it were, dove- 
tailed into each other. The articulations of the greater part 
of the bones of the skull are of this kind. 

Sym'physis. a union of bones. The bond of such union. The 
aggregate of means used for retaining bones in situ (natural 
situations) in the articulations. The name symphysis has, 
however, been more particularly appropriated to certain artic- 
ulations, as the ' symphysis pubis,' ' sacro-iliac symphysis,' &c. 



254 A^OCABULARY. 

T. 

Teleosts (or Teleostei). The name of that sub-class of fishes 
which embraces the great majority of living species, and so 
designated (by Johannes Miiller) on account of the ossified 
condition of the skeleton in all the representatives of the 
group. Tlieodove Gill. 

Tekatol'ogY. a treatise on monsters. 

Ter'tiary. Third ; of the third formation. In geology, a 
series of s.'irata, more recent tiian the chalk, consisting of 
sandstones, clay beds, limestones, and frequently containing 
numerous fossils, a few of which are identical with existing 
species. It lias been divided into Eocene, Miocene, and Pli- 
ocene, which ses. Dana. 

Tinctd'ra Myrrhs. (Tincture of Myrrh.) Tonic, deobstruent 
(removing obstructions), antiseptic (opposed to putrefaction), 
and detergent. It is chiefly used in gargles, and is applied 
to foul ulcers, spongy gums, &c. 

Tissue. By this term, in anatomy, is meant the various parts 
which, by their union, form the organs, and are, as it were, 
their anatomical elements. ' Histological anatomy ' is the 
anatomy of the tissues, which are the seat of the investiga- 
tions of the pathological anatomist. The best division, in- 
deed, of diseases would be according to the tissues mainly 
implicated. 

Tox'ODON. 'A gigantic, pachydermatous quadruped, now ex- 
tinct, having teeth bent like a bow. Brande. 

Transuda'tion. (To sweat.) The passage of a fluid through 
the tissue of any organ, which may collect in small drops on 
the opposite surface, or evaporate from it. 

Trephine'. Tlie instrument which ha,s replaced the trepan in 
some countries. It consists of a simple, cylindrical saw, with 
a handle placed transversely, like that of a gimlet; from the 
center of the circle described by the saw a sharp little per- 
forator, called the center-pin, projects. The center-pin is 
capable of being removed, at the surgeon's option, by means 
of a key. It is used to fix the instrument until the teeth of 
the saw have made a groove sufficiently deep for it to work 
steadily. The pin must then be removed. Sometimes the 
pin is made to slide up and down, and to be fixed in any 
position, by means of a screw. 



MINUTE, ROD-SHAPED PARASITES. 255 

Tro'car. An instrument used for evacuating fluids from cavi- 
ties, particularly in tiscites (serous fluid in the abdomen, or, 
more properly, dropsy of the peritoneum), hydrocele (watery 
tumors;, &c. A trocar consists of a perforator, or stylet, and 
a canula. The canula is so adapted to the, perforator that, 
when the puncture is made, both enter the woimd with facil- 
ity : the perforator being then withdrawn, the fluid cscaj^es 
throui?h the canula. 

Tubercle. MUiary tubercles are minute, bright, rounded, trans- 
lucent particles, called granula, granulations, &c. When 
they coalesce, forming larger bodies and undergo a change of 
color they are known as crude or yellow tubercles. As age 
advances, the center is apt to be occupied by a giant cell, a 
large multi-nucleated body, whose boundaries and processes 
are hard to define, because they shade off gradually into the 
surrounding tissue. They are the result of an inflammatory 
process, because they can be produced by the introduction 
of mechanical irritants. In some instances we have reason 
to believe miliary tubercles may become organized and a 
cure result. Tuberculosis is hereditary, and there is some 
good evidence to prove it is contagious ; it is also inoculable, 
and '* breeds true," always producing its kind, if it produces 
anything, but it has not been satisfactorily proved to have a 
specific virus. T. E. Sutterthwaite. 

(Dr. Koch of Berlin says (1882) tuberculosis is caused by 
minute, rod-shaped parasites (bacilli) ; that he has inoculated 
animals with them, producing tuberculosis; tliat he has 
dried the sputum of phthisical patients for two months and 
has bred the parasites artificially for several generations 
without their losing the power of inoculation ; that when 
the sputum is dried the air is infected ; that bovine and hu 
man tuberculosis are identical ; that tuberculosis can be 
given to man by the milk (perhaps flesh also) of tuberculous 
cows. The parasites are about _J-^th of an inch in length.) 

Tunic. An envelop ; as the tunic of the eye, stomach, bladder. 

TuRGZS'cENCE. Superabundance of humors in a part. ' Tur- 
gescence of bile " was formerly used to denote the passage of 
that flui^ into the stomach and its discharge by vomiting. 

Tympanites. A flatulent distention of the belly ; tympany. 
Also inflammation of the lining membrane of the middle ear. 



256 VOCABULARY. 

V, 

Un'gulate, Shaped like a hoof. Having hoofs, as ungulate 
quadrupeds. Webster. 

U'vEA (from uvea, a grape). The choroid coat of the eye ; the 
posterior layer of the iris. 

U'vEOUS. Resembling a grape ; applied to tlie choroid coat of 
the eye. 

V. 

Vas'cular. That which belongs or relates to vessels — arterial, 
venous, lymphatic — but generally restricted to blood-vessels 
only. Fall of vessels. 

Velum Pala'ti. The soft palate. 

Vek'tebr^. The bones which form the spinal column. 

Vis'cus (plural, vis'cera). One of the organs contained in the 
great cavities of the body ; any one of the contents of the 
cranium, thorax, or abdomen ; in the plural, especially ap- 
plied to the contents of the abdomen, as the stomach, intes- 
tines, &c. Webster. 

Vit'reous. Of, pertaining to, or derived from glass. The vit- 
reous humor of the eye is so called because it resembles 
melted glass. 

Z. 

Zooi/OGY. That part of biology (science of life) which relates 
to animal life, and, as generally understood, the science 
which treats of the structure, classification, distribution, hab- 
its, and derivation of living animals. In its broadest sense, 
however, zoology includes the structure, relations, and his- 
tories of extinct as well as living forms ; but this branch of 
the science is generally considered by itself under the title 
of ' paleontology.' The derivation and life-histories of many 
groups of animals have been found written in the records of 
the past, and many mysteries, not only of relation but of 
structure, have been solved by going back to find dwarfed 
organs in full development and widely-separated forms linked 
together. The zoology of the future will therefore include 
the animal life of both the past and the present. 

J. S. Neicberry. 

Zygomat'ic. That which relates to the zygoma or cheek bone. 



APPENDIX. 



RECENT DISCOVERIES OF FOSSIL HORSES. 

BY J. L. WORTMAN. 

The contributions to the knowledge of the extinct Perisso- 
dactjla,* made during tlie last two or three years in this 
country, are of an important character, since they demonstrate 
the actual existimce of types heretofore hypotlietically assumed. 
The living representatives, the horse, tapir, and rhinoceros, 
constitute but a small fraction of this large order when com- 
pared with the fossil forms already known. One of these, 
however, the horse, displays the most specialized structure to 
be found within the limits of the order. 

Many years have elapsed since the first discovery in the 
Tertiary rocks of Europe of horse-like remains, which are 
regarded by paleontologists in the light of direct ancestry of 
existing etjuines. Since then the discovery of the remains of 
these animals in the same geological horizons in this country, 
by Drs. Hayden and Leidy, has strengthened tlie belief in the 
descent of the horse from very different ancestral types. Entire 
ekeletons, obtained from the " bone beds" of the West, display 

* Odd-toed. The Perissodactyla may be defined as mammals having 
both pair of limbs fully developed and adapted for walking- or running-, 
the toes having terminal phalanges, incased in strong corneous sheaths, 
developed as hoofs. These characters, however, apply to two other orders 
also, the Artiodactyla (cloven-hoofwl or even toed), and the Ambhpoda 
(short-footed), both of which, however, possess many anatomical differ- 
ences fi.-oia the P(erissodactyla, particularly in the structure of their hiud 
limbs. 



258 . APPEKDIX. 

their osteological characters to sucli an extent as to leave no 
doubt as to the correct determination of their true affinities. 

It is much to be regretted, however, that many of these 
animals have received different names from diflPerent authors, a 
fact specially conducive to confusion in the nomenclature of the 
science. It appears that the only way to obviate this difficulty 
is by strict adherence to priority in the employment of a name, 
provided it is accompanied by a competent description, and the 
use of such characters as will distinguish the animal named 
from its nearest allies. If unaccompanied by these differential 
characters, it is a nomen nudum, and can have no claim what- 
ever to rank with those that have been properly defined. I 
mention these facts with the hope of establishing a criterion by 
which to judge which name it is proper to retain and which it 
is proper to discard ; and, to elucidate the subject, I will gives 
the names of a few animals that have been discovered during 
the past forty years. 

In 1841 Prof. Richard •Owen described the remains of a 
Lophiodon-like* animal, from the London clay of Eocene age, 
to w^hich he gave the name Hyracotherlnm.\ Subsequently he 
described a nearly allied genus, from the same deposit, under 
the name Pliolophus.X In Hijracothcrlum the molar and pre- 
molar teeth are different, both above and below. In Pliolophus 
the last, or fourth inferior premolar, is like the first true molar, 
a character which separates the two genera satisfactorily. The 
specimens described by Prof. Owen do not display clearly the 
number of digits either possessed, but he expresses the opinion 
that Pliolophus has three toes on the posterior limbs. 

* The Lophiodons were first described by Cuvier. They were allied to 
the tapir. They derive their name from the structure of the true molars, 
which have tl\eir crowns crossed transversely by two crests or ridges of 
dentine, covered with a layer of enamel. The last lower molar has also a 
small posterior lobe. The premolars are more simple in structure and 
compressed, resembling the first premolars of the tapir. The upper molars 
also resemble those of the tapir, but approach in some respects those^ of 
the rhinoceros. The diastema, or toothless interval between the canine 
and premolar teeth, was much shorter than in the tapir. Several species 
have been described from the Eocene of France and England, but little is 
known of the skull or skeleton. No true Lophiodon is yet certainly known 
in this country.— 0. C. Marsh. 

f Transactions London Geological Society, 1841, pp. 203-208. 

% Loc. Cit., pp. 54-72, 1858. 



CONFUSION IN NOMENCLATURE. 259 

In 1872 Prof. 0. C. Marsh found the remains of an animal in 
this country in deposits of Eocene age to which he applied the 
name Orohippus.* This genus was originally founded on the 
molar teeth, which he compared with those of Anchitherium. 
He subsequently ascertained that it possessed four toes on the 
anterior and three on the posterior limbs. f He also proposed an- 
other genus under the name of Bohippus, j^. which he compared 
witli Orohippu-% stating that the last inferior premolar is like 
the first true molar, a character which at once distinguishes it 
from HyracMherium. As he assigns no other dental characters 
to this genus sufficient to separate it from Pliolophus, with 
which, according to his description, it otherwise agrees, and as 
the digital formula in the Lopliiodons generally is 4—3, the 
two names must be regarded as synonymous. This may like- 
wise be said of the genus Orotherium ,% which Prof. Marsh 
distinguishes by the bifid condition of the antero-iuternal lobe 
of the inferior molars. This character is also ascribed to a 
number of molai- teeth discovered by Dr. Joseph Leidy in the 
Bridger Eocme, which he referred to the genus LopJiiotheriiim, 
SinesxvdUy of Pliolophus. But as this is a character of very 
doubtful generic value in this group of animals, these names 
must be regarded as synonymous wiih Piidoplius. 

Assuming then that the most generalized form in the ancestry 
of the hors'3 hitherto known was Hyracotherium, with a digital 
formula of 4—3 and teeth of the Lophiodon pattern, we are 
now prepared to take a step backward to the primitive five-toed 
ancestor, Phenacodns. But before entering on a discussion of 
this interesting form, it is necessary to mention the discovery 
of another genus, from the Lower Eocene beds of Wyoming, 
which proves to be a near ally of Hyracotherium. This genus 
Prof. Cope calls Sys'.emodon,\ and assigns as his reasons for 
separating it from Eyracotherium the circumstance that it dis- 

* American Journal Science and Arts, 1872. 
t Loc. Cit., p. 247, 1874, 

* Loc. Cit., Nov., 1876. The genera Orohippup, Eohippus, Miohippus, 
and Pliohippus have not in my estimation been distinguished from genera 
previously described ; hence my reasons for adopting names more in 
accordance with the prevailing nomenclature of the Kcieuce. 

§ Loc. Cit., 18?2. 

I! .-\mcricaii N-turali^t, 1831, p. 1018. 



200 APPENDIX. 

plays no diastemata (spaces) behind the superior canines, wliile 
in the latter there are two. This fossil (from Xew Mexico) was 
first described by him under the name Ilyracotherium tapirl- 
num, but the discovery of better specimens demonstrates its 
claim to the rank of a new genus. 

PHENACODUS. 

Phenacodus, one of the most important of recent paleon- 
tological discoveries, was first made known by Prof. Cope in 
1873,* from several molar teeth which he obtained from the 
New Mexican Wasatch. Its systematic position in the mam- 
malian class v^^as, however, involved in considerable uncertainty 
till the discovery of the greater part of the skeletons of two 
distinct species of this genus by the writer in the Wyoming 
Wasatch during the summer of 1881, which aflbrded Prof. 
Cope til e means of determining its true position and elucidat- 
ing the many important and interesting points its osteology 
teaches.f It possessc^s five well developed toes in functional 

* Paleontological Bulletin, No. 17, Oct. 1S73, p. 3. 

t I'rior to the discoverv of these skeletons no characters had been found 
among the Unj^ulata ^vhich indicate a group connecting the Perissodactyla 
with the elephants and hyrax.* But it is now necessary to create a new 
order, which Prof. Cope designates the ConGylarthra. (Paleontological 
Bulletin, No. ?A. Dec. 18S1, p. 177). The characters on which this division 
reposes are found in the carpus and the astragalus (hock or ankle bone) 
and their manner of articulation. The Perissodactyla are distinguished by 
the fact that the scaphoid articulates with two bones below, and the astra- 
galus articulates inferiorly by two nearly flat facets with the cuboid and 
navicular bones. They are divisible into ten families, including forty-eight 
genera, variously distributed throughout geologic lime ; but as only four 
of these families concern us for the present, I will spare the memory of the 
reader by not discussing the classification of the others. The first to which 
attention may be directed is the Lophiodontidx, embracing eight well de- 

* A gray-haired, rabbit-sized pachyderm, with 4 toes on the forefeet, 3 
on the hind, a mere tubercle for a tail, molars resembling (in miniature) 
those of the rhinoceros, 2 large, triangular, curved, tusk-like incisors in the 
upper jaw, and 4 straight ones in the lower. Ciivier savs the upper jaw, in 
youth, has 2 small canines, but Marsh's dental formula is: Incisors. 1—2, 
1—2: canines. 0—0, 0—0; premolars, 4—4. 4—4; molars. 3— .3, 3—3-34. 
There are several species, the African being able to climb a tree. The 
Cape hyrax is called the rock-baager or rock-rabbit. The hyi-ax was long 
classed among the r; dsnts, and was also called a miniature rhinoceros. 
There are various aftiniries between the elephant and some rodents— (1) in 
the size of the tusks ; (2) in the molars being often formed of parallel lam- 
inae ; (,3) in the form of several of their bones. 



RELATION 01- PUEXACODUS TO AMBLYPODA. 261 

US3 on all the feet, of which the first is the smallest ; the 
median is the largest and is symmetrical within itself. The 
feet are considerably shortened and were probably semiplanti- 
grade ; in fact tlie feet of this animal constitute an approach 
to the Amblypoda.'" The dcntul formula is : Incisors, 3 — 3, 

fiued genera, which are not positivclj' known to have existed later than 
the upper Eocene epoch. It may be recognized ^1) by the possession of 
four toes on the anterior and three on the posterior limbs ; (2) by the 
raolar and premolar teeth being dilTerent ; (3) by the non-separation of the 
anterior and posterior esternal cusps of the superior molars by an external, 
rib-like pillar. The next family is the Chalicothenidce^ to which ten genera 
are referred. Tlu; digit:il formula is the same as in the LophioJontidcB. as 
is also the relation of the molar and premolar teeth. The only distinction 
is found in the separation of the anterior and posterior external lobes by a 
vertical ridge. The remains of this family range from the lower Eocene to 
the middle Miocene. The third family is the Paleotheriidce^ having three 
toes on each foot. The molars and premolars are alike, and the inferior 
molars possess perfect double crescents. The fourth family is the Equidce, 
in which the digital formula is reduced to one toe on each foot. The mo- 
lars and premolars arc alike and highly complex in structure. It is to this 
family that all the existing horses belong, and it has been traced as far 
back as the upper Miocene strata. The Condylartkra, on the other hand, are 
cilectually separated from the Perisodactyla by the non-alternating posi- 
tions of the carpals and by the possession of an astragalus whose distal ince 
is convex in every direction, as in the carnivora, and unites with the navic- 
ular alone. These families are the Phenacodontida and Meniscotherndte 
v.hosc remains have been fotmd so far only in the lower Eocene deposits 
of this country. It is interesting to note that they are the most generalized 
of -any known Porissodactyla and supply a link long sought in the evolu- 
tion of the later and more specialized forms of this order. 

* There has probably been no discovery among the ungulates since the 
finding of the Amblypoda that has proved equal in interest and importance 
to the discovery of this group (the Phenacodontida?). The descent of ail 
the ungulates from the Amblypoda has been held by Prof. Cope for some 
time, but that it took place from any known genera of this order the Com- 
paratively specialized condition of the teeth of the latter distinctly forbids. 
This moderate comi)lexity of the teeth among Eocene mammals is a strik- 
ing exception, especially when associated with such a low grade of organi- 
zation of other parts as we find in these animals. The explanation of this 
fact must, in my judgment, be sought for in their large size and in the pos- 
session of powerful canine teeth, which insure them greater immunity from 
the attacks of fierce camivorous contemporaries. With these means of 
defense, they could take up their abode wdierc food better ada{)ted to their 
wants was fiirni.shed. Hence we can with perfect consistency look for 
a rapid modificatio^i of these organs, accoini)aiiied by slight change in 
others. In order to make the connection complete between them and the 
Phenacodonts, there should yet be fouud an Amblypod with bunodont 



262 



APPE^sDIX. 



3 — 3; cauin?s, 1 — 1, 1 — 1 ; premolars, 4 — 4,4 — 4; molars, 8 — 3, 
3 — 3=: 44 ; that is 44 functioually developed teeth. The molars 
are of the simple four-lobed pattern, resembling in this respect 
the suilline Ariiodactyla or liovrs and peccaries; in fact on this 
account it is a matter of some sui'prise that the animal should 



molars, reduced canines and a more elongated foot. An approach to this 
condition, as far at least as the molars are concerned, is found in a new 
form recently described by Prof. Cope under the name Manteodon (pro- 
phecy tooth). The Amblypoda, says Prof. Cope in his Report on Capt. 
Wheeler's Survey (W. 100th Mer., Pt. ii, Vol. IV, p. 233), are as yet con- 
fined to the Eocene peiiod exclusively, and are found both in Europe and 
this country. In points of affinity to the hoofed orders generally they 
occupy an interesting and important position, being in all probability the 
oldest and affording the most generalized condition known among the 
ungulates. The brain capacity is exceedingly small in proportion to the 
size of the other parts of the skeleton, and from casts made from the brain 

case itself we are warranted 
in assigning these animals 
a position among the low- 
est mammalia; they are 
lower in brain development 
even than any of the Mar- 
svpials. The feet are very 
short, are provided with 
five fully developed toes, 
and have their entire plan- 
tar and palmar surfaces ap- 
plied to the ground, as in 
the modern bears. The as- 
traaralus is greatly flattened 
from above downward, and 
is primitive and character- 
istic. It displays on its in- 
ferior surface flattened ar- 
ticular facets for both na- 
vicular and cuboid bonca 
which share the articula- 
tion about equally. On the 
superior part, the surface 
articulating with the tibia 
is almost flat, a condition 
which must have rendered 
the ankle joint capable of 
very little movement, and 
giving to these animals a peculiarly awkward and shambling gait. It is 
not difficult to perceive that these small-brainod, five-toed, nnd plantigrade 
Amblypoda could easily have furnished a starting point for both the Artio- 
dactijla and Perisf^odactyla, and, as we have good reasons to believe, did 
give origin to the Proboscidea or elephants. 



f 

c 




'^ 



''^-"■'''fllllillll'f 

5te 



\js>»*' 



cS^ ^l?j 






RiKDt Iiind-foot off 



species of Corvphodo 



(Amlilypod), imlf 



HOUSES WITH TEETH SIMILAii TO REPTILES'. 2C3 

turn out not to belong to the suillincs. But wlien the evi- 
dence of derivation drawn from other sources is considered, 
and the geological period is taken into account, the struciure 
of the teeth is preeminently in accordance with the expecta- 
tions of the evolutionist. It is jraportant to notice in this con- 
nection that Prof. Cope ventured the prediction in 1874* that 
the quadritubercular or four-lobed huuodont f molar was the 
primitive pattern in which the more complicated selenodont X 
molar of the later ungulates had its origin. That this predic- 
tion is now proved there can be no question, and the passage 
from this simple type of tooth to the highly complicated forms 
illustrated in this article has, I think, been close and consecu- 
tive and intimately associated with reduction in digits. 

The Phenacodontidge present considei-able variety as far as 
their family is at present known. Prof. Cope has described 
five genera, as follows: Pheuacodus, Anacodon, Protogonia, 
Periptyclius, and Anisonchus. The first two are from the 
Wasatch horizon, while the last three were derived from the 
underlying Purco beds. Periptychus shows a peculiar sculp- 
turing of the outside of the molar teeth, similar to that seen in 
many reptiles, and is the only mammal known to possess it. 
The molars of Anacodon lack distinct tubercles, a character 
which assigns it the lowest position in the family. Phenacodus 
approaches nearest to the Lophiodons in dental character and 
is taken for illustration. As all but Phenacodus and Peripty- 
chus are known from their teeth only, it may be necessary on 
the discovery of the character of their feet to refer them to new 
families. The definition of the family given by Prof. Cope is 
as follows : Molar testh tubercular ; molars and premolars 
different ; five toes on all the feet.g 

MENISCOTHERIUM. 

The Meniscotheriidae has been recently established for the 
reception of the single genus Meniscotherium, discovered by 

* Journal Academy of Natural Science?, Fliiladelphia. 

t Teeth of !^iml)le ytnicture. with short crowns and low, Wuut tubercles 
on then* f ice. 

* Teeth of coipplicatcd structure, with high and uniformly broadened 
crowns, the face presenting a complex folding of the enamel plates. 

§ Paleontological Bulletin, No. 34, Dec, 1881, p. ITS, 



2C4 APPEi^DIX. 

Prof. Cope in tlie Wasatcli beds of New Mexico, and described 
by liiiii in his report to Captain WlieeL?r, already cited. It 
was formerl/ arranged in the GhalicotheriidcB, near Challcothe- 
riain, with which it agrees in all essential dental characters. 
The recent discovery of the bon^ of the feet shows that they 
display the charactjristic peculiarities of the CondylarthTcty to 
which group it must be referred. Its digital formula is 
unknown, hence we must rely on the sj.ecialized crescentoid 
pattern of the molars for ths family deiinitiou. It is proper to 
remark here that reduction in digits in the Perissodactyla is 
usually accompanied by specialization of the molar teeth. In 
this case, therefore, I would venture the prediction that its 
digital formula will be found to be 4 — 3, with the outer toea 
somewhat reduced. Tiie value of the digital formula as a 
character in the definition of the families of the Perissodactyla 
i3 of hiiih standard. This may likewise ba said of the rela- 
tion of the molar and premolar teeth, but in a less degree. 
Tli3 tubercular or cresceiitoi:! structure of the molars, however, 
is capable of such intergradation, which increase of ourknowl- 
edge demonstrates, that it must be accepted as provisional 
only, and not entitled to rank equal in value to either of the 
other two characters in defining the family. 

The genealogy of the horse as now indicated is as follows : 



Equus, Equus, 

Protohippus, Hippotherium^ 

Auchippus, Paloplotherium, 
Ancliitherium, 
Mesohippus, 
Lambdotherium, 
Hyracotherium, 
Systemodon. 



Perissodactyla - - 



Amblypoda, Hyodonta (Cope). 



OoNDYLARTHRA - ■% Mcniscotherium, 

f Phenacodus. 



MATURE S METAMOKPIIOSES. 



265 




206 



APPEl^DIX. 



a.e V 



acc- 




pe 



pee 



ail 



pi 



pe ae 




pi z ai 

2 



W9^^ pi 



acc 




ue 



TEETH rnOM PIIEXACODUS TO EC^UL'S. 2(i7 

1.— Left upper molar of a species of Phenacodus, nat. size (Cope) ae is 
the antero-exionial, /;<;- the iwstero-extcnuil. ai tiie ajitero-iiiteru;il and pi 
the postero-iuteruai lobes respectively. They are low and obtuse and con- 
stitute the priiicii)al ciu^ps of the crown, ace and i)cc are the anterior and 
posterior cross crests , they are riulinientary and represented by isolated 
tubercles in this animal, but are developed into important structures in the 
more specialized genera, y (the lobe ii? drawn too large) is the rudimeutal 
external rib separating the antero and postero-external cueps. An antero- 
basal lobe arising as an outgrowth Ironi the cinguliim or ledge surrounding 
the base of the crown is strongly marked in some genera. • 

2.— Left lower molar of same. uat. size, z represents a lovv, indistinct- 
ly marked ridge, passing from the postcro-external to the antero-internal 
cusps pe, ai. The antero-internal cusp ai is sometimes double, h is the 
heel, which is so strong in the last molar as to be called a fifth lobe. It ia 
connected by a faint ridge with the postero-external cusp pe. The four 
principal cHsps ae, pe^ ai, pi hold the same relation to the crown as in the 
upper molar. 

3.— Right upper molar, of a species oi Lambdotherinm, in which the an- 
tero and postero-external cusps ae,p€ are separated by an external vertical 
ridge, y ; nat. size iCope). 

4.— Last lower molar (left side), of same ; nat. size. The antero-in- 
ternal lobe is divided into two distinct tubercles, ai, ai'; the ridge k is 
strong and prominent. The breadth of the tooth is accounted for by the 
fact that it is the last molar, the first and last molars being about a third 
broader than the others. The teeth are of a more complicated pattern than 
those of Phenacodus. It is important to notice'that while the teeth of the 
lower Eocene genera of this family (Lambdolberiiim and Paleosyopous) re- 
semble very strongly the teeth of the lower forms of the Lophiodons in the 
shortness of their crowns and approach to the bunodont type, the latter 
possess longer cusps and simulate the seleuodont forms in the cresceutic 
section of some of them. 

5.— Left upper molar of Atichitha-vim anreliaxionf^e, nat. siz-^ (Gaudry). 
The four principal cusps ae^ pe, ai. pi are considerably lengthened and con- 
nected by high ridges, ace. pec, which pass in an oblique direction across 
the crown. The elevation of the cusps and crests give increased depth to 
the valleys. The anterior basal lobe is reduced and the external rib y is 
strong. The crown is further complicated by the addition of the lobe /. 

6. —Right upper molar of a species of IRppofherivm. The valleys, which 
are deepened by the lengthening of the cusi)s and ridcres, are filled by a 
thick deposit of cement, but the cement, as the cut shov>s. has been re- 
moved. The points of the cusps and ridges are unworn. The four princi- 
pal lobes ae, pe. ai, pi hold about the same relation to each other. The 
cross crests ace, pec have their obliquities increased, and the anterior bends 
around on the inner i)art of the face and becomes confluent with the pos- 
terior ridge 7>C(7. The lobe I, which is conic in Anchitherium, is elongated 
in a transverse direction to the crown, so as to close the posterior valley 
and join the posterior external cusppe with the posterior crest pee. Addi- 
tional vertical pillars are developed on the cross ridges. The teeth resem. 



268 APPEXDI 

ble tliose of the horse very strongly, the crov.ns of the incisors showing 
the i)eculiar invagination t^een in the inciisors of the horse. 

7.— Left lower molar of HippoUierivm gracile. three-fourths natural size 
(Gaudry). The lobe ai' is now completely separated and the ridge k rises 
to a level with the other cusps. The heel h is also elevated and connected 
by a strong ridge. The filling up of the valleys by a deposit of cementum 
and the consequent attrition in mastication produce' a maVked change in 
appearance from that seen in Anchitherium, but by close observation the 
strictest homology is seen to exist. 

8.— Left upper molar of a species of Eqnvs (modem horse) natural size. 
The internal lobes ai in are connected with the cross ridges ace, pec. The 
only difference of generic value between Equus and Hippidium (a near rela- 
tive of the horse) is seen in the relative size of the antero and postero-in- 
ternal lobes ai^pi ; in Equus ai is greatly enlarged and somewhat Ilaiteued; 
lu Hippidium the lobes are almo&t equal. 

What has caused these chanores? In regard to tooth struc- 
ture generally, Mr. J. A. Ryder has given us a most excellent 
treatise " On the Mechanical Genesis of Tooth Forms,"* in 
which he shows that the jb.w movements of animals are 
intimately related to the modification of the component lobes, 
crests, and ridges of the crowns of the molar teeth. He also 
points out that the restricted jaw movements, in which the 
mouth is simply opened and closed, are associated with the 
bunodont molar ; that the various kinds of excursive mandib- 
ular movements have been developed progressively; "tliatr.s 
these movements have increased in complexity there has been 
increase in the complexity of the enamel foldinp:s." 

If we attempt to apply these facts to the ancestry of the horse, 
it is by no means difficult to perceive that gradual change of 
habitat, causing a corresponding change in diet, would also 
compel greater and greater mobility of the mandibular articula- 
tion for proper trituration of the new food. The movements of 
the lower jaw in these animals have assumed a lateral direction, 
which affords, as T believe, a sufficient explanation for the 
broadenincT of the crowns and the lateral flattening of the cusps. 
The obvious effect of force continually applied in this direction 
would be to wrinkle the enamel covering of the cusps and 
ridges, thereby producing the accessory pillars seen in the 
higher types. By this method, I believe, a more and more 
complex grinding surface has been produced. 

* Proceedings Academy Natural Sciences, Philadelphia, 1S~8. 



CAUSE OF DIGITAL KEDLX'TION". '^60 

The cause of digital reduction is another interestinfr inquiry. 
Bunodonts as a rule' are dwellers in s\vami>s and forests and 
live on nuts, berries, and roots. If they are compelled to for- 
sake their natural habitat and live in the open field, either 
modification or extinction will follow. Once in the o[)en field 
speed becomes a desideratum as a condition of safety, and the 
f(;ot with a reduced number of digits possesses many advan- 
tages over the polydactyle one. 

Prof. Cope has shown {American Naturalist, April, 1881) 
that in plantifjrade quadrupeds the extremities of the toes are 
arranged in a semicircle, when they are all applied to the 
ground. In the act of running the 1.-j1 and wrist are raised, 
throwing the weight of the body on the median digits. An 
infinite repetition of this posture in digitigrade animals unable 
to withstand the attacks of their enemies and whose only 
escape was in flight, the strengthening of the median digits. 
and th(^ consequent reduction of the outer ones, would follow 
according to the law of use and disuse of parts. This subtrac- 
tion of toes has progressed step by step until the modern one- 
toed horse has been reached. 

In summing up an article in the Kansas City Bevieic of Science 
and Industry, Mr. Wort man says : 

"I dare say that if all the intervening individuals between 
Phenacodus and Equus could be produced classification would 
be utterly impossible, so insensible would be the gradation." 

The forms already known appear to point to the inevitable 
conclusion that the modern horse is the product of the slow 
but iciprovJng processes of evolution, which are still in opera- 
tion, and are being aided by all the skill known to modern 
science. A discussion of the subject is almost superfluous, for 
the illustrations, like deeds, speak louder than words. 

iVote.— Pliny (B.C. 23) says Caesar had a 5-toecl horse (the forefeet), which 
was represented in his (Pliny'?) day by a statue ; also that Epi>,'enes eay? the 
Babylonians had a series of observations on the stars for a period of 720,000 
years, inscribed on baked bricks. Bjrosns and Critodemus say 490,000. 
(Vol. ii. p;x 2-21-317.) Haked brieks have been found buried in tlie valley 
of the Nile at a depth to require the annual deposits of that river for 0,000 
years (72 feet.) May they not some day be valuable aids to science as well 
as history ? Their stories can be better Jniagined than depcilbcd 



270 APPENDIX. 



THE VIEWS OF AN EVOLUTIONIST. 

The following "review" of Horses' Teeth, written by 
Mr. R. M. Tuttle for Johnstons' Dental Miscellany, contains so 
mucli of interest on the subject of evolution that I think no 
apology necessary for inserting it here instead of putting it 
among the other press reviews at the conclusion of the volume : 

" The author of this work modestly suggests that it may be 
of value to the veterinary profession and also to horsemen and 
farmers. We have no hesitation in going further and affirm- 
ing that it contains much of an instructive and interesting 
character for dentists, and all scientific and thoughtful men. 
The day has gone by when humanity laughed or grew angry 
(according to its temper at the moment) at the mere suggestion 
that man has any relationship with the lower animals beyond 
their submission to his will and his right to lead them to the 
slaughterhouse. The movement of thought in the direction 
of Evolution is battled against by some eminent thinkers. The 
book before us does much to upset the arguments of these 
thinkers and to support the theory they denounce. But there 
is a middle position for those who neither agree with the theory 
of a separata creation for every genus nor with the develop- 
ment of animal life from one germ form. This position may 
be described in the words of Tennyson as a ' sunless gulf of 
doubt.' Doubt, however, is not always sunless ; and besides 
to admit a doubt is at least frank, and we prefer it to being 
dogmatic. Still even believers in a separate creation for every 
genus cannot but admit that, notwithstanding the . great 
diversity in the animal kingdom, there is a oneness of princi- 
ple, a common style of architecture, so to speak, pervading all 
animal life, which we see in the structure of teeth, arms, legs, 
wings, &c. 

"The construction of a horse's teeth points to the inevitable 
conclusion that he is a vegetarian, but the various changes in 
the dentition of a long line of fossil horses indicate that he was 
once probably carnivorous, or perhaps omnivorous. Teeth, 
like other parts of the body, are influenced by use ; the change 
is not so ob\dous, but it is no less certain. As the volume 



THE WEDGE OF EVOLUTION. 271 

before us affirms, for example, the canine and remnant teeth 
have been much reduced in size, and, if Mr. Darwin's theory- 
is correct, are probably in the course of ulfiraate extinction. 
Now, the function of a canine tooth is to tear, not grind. If 
animals that now use their canines for tearing flesh were com- 
pelled to subsist on vegetable food, there would perhaps be no 
marked change in a generation, but there certainly would be 
in a series of generations. We therefore conclude that horse 
dentures have adapted themselves to a gradual but great change 
in the animal's mode of existence, a gradual departure from 
the original custom of subsisting on food wnicli demanded 
tearing teeth, and that it took to vegetarianism naturally. 
Fossil remains would force this conclusion on us, however 
much we might desire to doubt it. But why should we have 
such a desire ? To admit development, say some, is but the 
thin end of the wedge of Evolution. Be it so. It is the func- 
tion of scientific wedges to split old and false notions, and who 
ever heard of a man putting the thick end of a wedge in first? 
Whether development is the thin end of the wedge of Evolu- 
tion or not we do not care much to inquire. If a man studies 
horses' teeth of to-day as well as those of human boings, he 
will come to the conclusion that in both there are signs of great 
develnpment when com|-)ared w^ith the teeth of thousands of 
years ago. He will observe not change merely, but signs of a 
higher order of being — signs of an ev^olution of the superior 
from the inferior. 

" To some people Evolution is a bugbear, and the idea that 
human beings are capable of physical development is not much 
less. We advise such ]>eople not to read Mr. Clarke's book. It 
would trouble them. They might cast it into the fire and thus 
waste their money. But intelligent seekers after truth, those 
who find the 'gulf of doubt' in which they are floundering 
too sunbss for their light-loving souls ; those who are not 
afraid to meet the doctrines of scientific men face to face, may 
read this work with profit. Without desiring to disparage its 
author, we may say that its chief value lies in the fact that it 
is composed largely of selections from the works of men of 
special knowledge on the subject of the treatise and of various 
germain subjects. Much credit is due to him for collecting in 
so compact a form sucli a large quantity of valuable matter. 



272 APPENDIX. 

which was scattered over cyclopedias, translations of learned 
secieties, and other costly books." 

Mr. Tuttle, in a letter to me (a few words of which have 
been interpolated in the foregoing article), in substance says : 

" At the close of the Eocene period there were three distinct 
types of animals descended from a common ancestor that are 
now represented by the horse, tapir, and rhinoceros.* Let us 
suppose that a pair of animals gave birth to the offspring which 
were to be the parents of these three types. What would be 
the process of development? These animals, with their mates, 
by some means get separated. The parent of the future tapir 
goes one way ; that of the rhinoceros stays at home, while he 
who is to beget the horse wanders away from the marshes and 
rivers to tha dryer land. Circumstances over which he lias no 
adequate control place him where alligators, crocodiles, and 
other animals that he has been accustomed to attack with his 
tushes are absent. His feet, which are many-toed, broad, and 
adapted to walking in the mud, now tread hard soil ; his canine 
teeth, which were used in tearing ii sh, now find little employ- 
ment ; his neck, from constant stretching as he crops the foliage 
of the bushes, lengthens ; a more rapid gait is acquired by a 
gradual contraction of tlie toer, and the lengthening of the legs, 
and eventually this modified animal becomes a horse. TIius is 
told in a few words what 1 believe has Icon g( ing on in the 
course of hundreds of thousands, perhaps millions cf years." 

It is noteworthy that a young man like Mr. Tuttle should 
entertain views similar to those of such an esperiencod evolu- 
tionist as Prof. Cope. It is not difiTicuU to believe that the 
bear-like Amblypoda, which Prof. Cope thinks were the com- 
mon progenitors of the hors3, tarir, rhinoceros, elephant, &c., 
were carnivorous, and there certainly is some analogy between 
the supposititious animal just described by Mr. Tuttle and the 
Amblypoda. Change of food was probably as instrumental in 
producing the great physical changes in early fossil animals as 
change of habitat and climate. And change of food does not 

* Compare with quotation from Prof. Huxley in third note, pp. 65-66; 
also with same from Prof. Owen, pp. 106-7. 



FOOD A FACTOR IN EVOLUTIOX PKOBLE^r. ^73 

necessarily entail extinction, unless it be food directly opposed 
to the animal's nature ; and it raatters not if the change Is 
compulsory, for changes of taste may be either natural or cul- 
tivated. For example, children relish food they cannot eat 
when adult, and vice versa, which is natural ; and an appetite 
for SDnij foods may be cultivated at any age. Again, food 
probably causjs much of the change in tame bears and other 
animals that become wild, and vice versa. Still it is not strictly 
correct to say that the horse as such was ever carnivorous, for 
an animal that was the common ancestor of so many diverse 
animals was as much one as the otlier. 

In 1878, in a hastily written prospectus of a work that Dr. 
€. D. House designed to publish, in conformity with his 
(House's) views, I said the horse was probably once carnivor- 
ous. Thinking Dr. House to be mistaken, I wrote to Dr. Leidy 
of Philadelphia, asking his opinion on the subject. He agreed 
with me. 



THE ORIGINAL HOME OF THE HORSE. 

There is no doubt that the original home of the horse is not 
Europe, but Central Asia; for since the horse in its natural 
state depends on grass for its nourishment and fleetness for its 
weapon (safety), it could not in the beginning have thriven 
and multiplied in the thick forest-grown territory of Europe. 
Much rather should its place of propagation be sought in those 
steppes where it still roams about in a wild state. Here too 
arose the first nations of riders of which we have historic 
knowledge, the Mongolians and the Turks, whose existence, 
even at this day, is as it were combined with that of the horse. 
From these regions the horse spread in all directions, especially 
into the steppes of Southern and Southeastern Russia and into 
Thrace, until it finally found entrance into the other parts or 
Europe, but not until after the immigration of the people. 
This assumption is at least strongly favored by the fact that 
the further a district of Europe is from those Asiatic steppes, 
i.e., from the original home of the horse, the later does the 
tamed hdVse seem to have made its historic appearance in it. 
The supposition is further confirmed by the fact that horse- 



27-4 APPEXDIS. 

raising among almost every tribe appears as an art derived 
from neigliboj-iug tribes in the East or Northea&t. Even in 
Homer tiie ox appears exclusively aa the draught-animal in 
land operations at home and in the field, while the horse was 
used for purposes of war only. Its employment in military 
operations was determined by swiftness alone. That the value 
of the horse must originally have depended on its fieetness, 
can easily be inferred from the name that is repeated in all the 
branches of the Indo-European language, and signifies nearly 
"hastening," "quick." T lie same fact is exemplified by the 
descriptions of the oldest poets, who, next to its courage, speak 
most of its swiftness.— y^/l<^ Popular Science Monthly for Jane, 
18S2. 



ELEPHANT TOOTH-GERMS. 

MM. Pouc.iET AND Chabrit (Le Pr ogres Medical), having 
examined the germs of the teeth of a fetus of an elephant in 
the Jar din des PI antes, have concluded that the general opin- 
ions on this subject are not exact. Since the works of Robin 
and Kolliker, it has been assumed that there is produced on 
the surface of the gum a primary epithelial bud (bourgeon), that 
Poiichet calls the epithelial plate and Kolliker the adamantine 
organ or enamel, which sends out a prolongation destined to 
form a temporary tooth, and afterward a second prolongation 
for a permanent tooth. The more recent experiments seem to 
prove that the pern^anent teeth are not given forth from the 
neck of the temporary, and that there is no secondary adaman- 
tine organ. In the elephant, where there is no second set of 
teeth, the same plate or layer appears, together with the same 
prolongations. The two faces of the epithelial prolongation 
do not have the same structure ; the inner face is composed of 
cylindrical cells, while in the outer face there is a mingling of 
epithelial and tissue cells.— iV. Y. Med. Times, Feb. ISSl (trans- 
lated by Dr. T. 31. Strong). 

The deductions of MM. Pouchet and Chabrit may be correct 
in principle, but it is a mistake to say the elephant has only 
one set of teeth, for he has six or more, and may in fact be said 



THE ELEPHANT TEETH IX(; ALL THE TIME. 275 

to be always teetliiug. The following facts arc partly based 
ou Cuvier, Oweu. and Wm. Jacobs: 

The crrinders, wliich are constantly in prog-ress of destruction 
and formation, are not deciduous in the ordinary sense, for they 
succeed each other horizontally instead of vertically, and not 
moro tlian one who'ly or two partially (one ou each side in each 
jaw) is in use at one time. As the fore part of tlie tooth in us3 
is worn away by attrition and its roots diminished by absorp- 
tion, its successor pushes it forward (a movement that appears 
to b'j facilitated by the direct backward and forward action of 
the lower jaw), and a large part of the rei)lacing tooth is in 
use for some time before the first is entirely shed. Tims a 
grinding surface is ready all the time. The milk teeth are cut 
eight or ten days afrer birth, the upper preceding the lower, 
ancl it IS about two years before they are entirely displaced by 
thj second set. The second set is in use, but gradually dis- 
appearing, from the second year to the sixth, when the third is 
fully in position ; it in turn serves till the ninth year, when 
the fourth set is in position ; and thus it continues to the end 
of the animal's life-10) or even 150 years. Each succeeding 
tooth requires at least a year more than its predecessor to be 
completed. 

The grinders are remnrkable for their size and the complexity 
of theirstructure, the upper and lower teeth being muc'.i alike. 
They are composed of ivory (dentine), enamel, and a large 
quantitv of cement. The crown is short in proportion to the 
depth Jf the baso or root, only a small part appearing above 
the o-nm. In the Asiatic species the crown is composed of 
transverse, vertical, enamel-plated dentine ridges, about half 
an inch apart, and joined together by cement. Tiie ridges are 
nearly strai<'ht and are tooth-like in appearance. The ridges 
are good indicators of nge, the Brst set of tee'.h having 4, the 
second 8 or 9. the third 12 or 13, the fourth 15, and so on to 
the seve-..th or eighth, which have 22 or 23. In the African 
species the crown is studded by lozenge- shaped projections in- 
stead of rido-es. A tooth of the elephant Columbus, an excellent 
specimen, which may be sem in Worth's Museum (New York) 
weighs 12 iTOunds ; its breadth is 7 inches (the aggregate of 
the six back teeth of the horse); thickness, 2^ ; length, 11. 



276 APPEi^DIX. 

It baa only 13 crown ridges, and is therefore little above a 
medium-sized toorh.-^ The crown resembles a small Belgian 
paving stone, while the taper of the root resembles that of a 
heart. 

The elephant is a vegetarian, and the construction of its 
grinders is a striking example of the adaptation of the teeth of 
an animal to its food. 

The tusks, two in number and belonging to the upper jaw, 
are shed but once. The deciduous tusks cut between the filth 
and seventh months and are shed about the end of the first 
year, their roots being considerably absorbed. , They rarely 
exceed 2 inches in length and h of an inch in diameter. About 
two months after the shedding of the temporary tusks, the 
permanent, which are situated to the inner side of and behind 
the former, emerge and continue to grow throughout life. They 
have an enamel coat, but are mostly composed of ivory , a 
remarkably fine and elastic form of dentine (differing somewhat 
from the dentine of other teeth), and are hollow for a consider- 
able part of their length. They are deeply imbedded in the 
skull. Sir Samuel Baker found one 8 feet long with 22 inches 
girth to be imbedded 31 inches. 

The tusks, which are formidable defensive and offensive 
weapons, and which correspond to the canine teeth of other 
animals, vary much in length, weight, and curvature. Gordon 
Gumming found a tusk in Africa that measured lOJ feet and 
weighed 173 jjounds. The average, however, is not over 7 feet 
and 109 pounds. They are generally smaller in the female 
than in the male, but according to Cuvier the African species 
are the same in this respect. In the Indian elephant some have 
a pronounced upward curve, some are nearly straight, while 
others resemble the letter S. They are sometimes used as 
levers in uprooting mimosa trees whose crown of foliage is 
beyond the reach of the trunk. In Ceylon, where the elephant 
lives chiefly on grass and herbage, the tusks are generally 
absent in both sexes. The bullets sometimes found in the 
ivory are probably first lodged in the pulp cavity and then 
carried to the solid part by growth. 



* Mr. L. G. Yates of Centerville, California, says fossil elephant molars 
weighing 25 pounds have been discovered in that State. 



HUMAN ^HUMAXE) DENTISTRY. 277 

A large elephant weighs 7,000 pounds. The Indian elephant 
is 10 feet in hight, the African 13 ; a skeleton in the St. Peters- 
burg Museum is IGi. 



HUMAN TEETH. 

FILLING children's TEETH.* 

Filling the deciduous or first set of teeth prevents decay 
and consequent injuiy to the second set,f alleviates pain, facil- 
itates syeech4 mastication, and legularity in the growth of the 
second set, aids in keeping the breath pure, and is conducive 
to health at a very critical time of life. They should be filled 
as long as filling will preserve their usefulness, and at all times, 
for some are shed as early as the fifth or sixth year, others 
as late as the eleventh or twelfth. Any of the usual fillings 
will answer, the sole object being to arrest decay and "aid 
somatic development " (Odell). Children should be taught to 
use a brush and proper dentifrices. Defective teeth are often 
the result of improper diet during utro-gestation. Drs. J. Allen 
and G. M. Eddy say that mothers do not eat enough bone- 
producing food, such as oatmeal, bread made from unbolted 
flour, &c., but admit that such foods do not assimilate in every 
case. Dentists differ as to the advisability of the use of 
anaesthetics in treating children. 

The teething period is longer than is usually supposed. It 
begins about the seventh month before birth § and continues 

* The object of this brief article is merely to call attention to an impor- 
tant subject. My own attention was directed to it by Mr. E. A. Rockwell 
in an interesting article in the New York Sun. Eeader? who wish to stncly 
the subject arc referred to the elaborate worts of dentists. Besides the 
dentists mentioned above I have consulted Drs. G. H. Rich, F. Abbott, and 
C. E. and J. S. Latimer, all of New York. 

+ Dr. T. P. Wa^joner (Knicrhtstown, Ind., Dental JSTeu's) approves the 
above, and in addition says the development of a permanent tooth may 
be retarded by a dead deciduous tooth. 

X Ilaller and other pbysioloofists j^ive minute accounts of the effects 
produced by teeth in articulating the various letters of the alphabet.— 
Bostock. , 

§ For the development of human tooth-germs from the seventh -week 
till birth see page 46. 



278 



APPENDIX. 




till the age of 17 or 25 years. The annexed cut (Farrar) repre- 
sents (above the dotted line) an upper deciduous set of teeth. 

1, 1, centra] incisors, erupt between the 5th and 6th months; 

2, 2, lateral incisors, 7th and 10th months ; 3, 3, canines (eye 

teeth), 12th and 
16th mouths ; 4, 4, 
5,5, all molars, 14th 
and 36th mouths. 
Total, 20. The low- 
er teeth usually 
precede the upper 
by a few weeks, 
6, 6 do not belong 
to the deciduous 
set, but, as they 
erupt between the 
fifth and sixth 

years, are usually classed with them, and frequently decay 
beyond remedy before the mistake is discovered. 

Dr. J. N. Farrar (New York), to whose works I am indebted 
for information, says {Missouri Dental Journal, April, 1880) : 
" The statistics in this country show that out of about 80 peo- 
ple of all classes only one has sound teeth. This is the result 
of a combination of causes — systemic disturbances from clinftite, 
food, crossino^ of races and types, and neglect. Most of the 
cavities are caused by anatomical imperfections or overcrowd- 
ing, nearly all of which develop before the thirty-fifth year, 
* * * The science of dentistry, however, has checked much 
of this suffering, and at this time (1879) there are 12,000 dentists 
annually ])acking into tooth-cavities about half a ton of gold — 
$500,000. The estimated gold coinage value in this country is 
about $150,000,000 ; this sum, at the rate gold is used for fill- 
ings, would be transferred to graveyards in 300 years. The 
value of the cheap fillings is about $100,000, and there are 
annually manufactured about 3,000,000 artificial (porcelain) 
teeth. * * * If $100 is put on interest (7 per cent.) at the 
birth of a child, it ought to pay all dental expenses till the age 
of 30 years ; but if the child's teeth are neglected, increased 
dental bills result, with poor teeth at best. The only question 
remaining is, is the baby worth $100 ? " 



INDEX. 



Ab^tor^taL DENTtTioN, human, 128 ; 
hor^e, U-2. 

Abnormal Teeth, 115-123. 

Abiioriual Tooth, descriijiion of, 123. 

Ab-ioi'ptioii of roots; of foals' teeth, 
48, 70-1 ; do. e.ephaiit, 275-6 ; den- 
tal journal on, 288. 

Alfort Vetermary College, 14 >, 142. 

Amblvpodii, the, 257 ; des^cription 
of. 261-2. 

Americi.^, the. richness of fossil re- 
mains in, 105-113. 

AnacoJon, fossil lior.':<e, 263. 

.\m.-Ilippus. fo!?!?il horse, 96. 

Anchitlieriuin, fossil hors^e, 96, 111. 

Auchitheriiini aureliauenie, teeth of, 
2jG-7 ; toes of, 265. 

Animal Kinsfdom, divr-rgity yet one- 
ness of principle In, 270. 

Animal, a «upposititio!is, 272. 

Anoploiliere, tcth of, 6.5. 

Antelop3 montana, tnshe3 of. 73. 

Anparatu-!, dental, exubsrance of 
particular parts of, 141-3. 

Appendix, fossil horses, evolution, 
original home of horse, elephant 
and children's teeth, 257 -277. 

Apsyrtus, advice of. 116. 

Arcad,^s (of teeth; anomalies in form 
of, 110, 141. 

Aristotle, mistalce of, 69. 

Arloinsr, M.. resection of nerves, 217. 

Armaiiiio, the, 229. 

Artiodactyla (lio.'s, &c.). 957, 262. 

Ass, experiment on an, 217, 213. 

Babingtox, B., 242. 

Bacon. Francis, theory of, 15. 

Baer, Von, comparisons by, 81. 

Bake;-, S., report of, 18t, 182. 

Batrachla, the, 229. 230. 

Bay, Surgeon, discovery of, 117. 

Beil, C, discoveries of, 217, 218. 

Bell. Thoma<, theoiies of , 26-7. 83-4. 

Berger-Perriere, discovery of, 116. 

Berzelius, discoveries of, 15. 



Birds, fossil, teeth of, 114. 

' Bishopiug,' modus operandi of. 211. 

Black. Surgeon, t-xpermient of, 29. 

Blaine, Surgeon, fractured jaw, 197. 

Blastema, nalure and color of, :34^. 

BUimenbach, on quidruniana, 251. 

Boar, the madied, griiulers of, 10. 

Boar, wild, tamo, changes in, 81, 273, 

BjII, Dr., tooth pulp, bl. 

Bojanus, disc..very of, 52. 

Bond's • Dental Medicine,' extract 
from, 1-23, 129. 

Bonlcy, M. H., development of teeth, 
45 ; giinders, 62 ; formation of 
enamel, 04; growth of teeth dur- 
ing life, 73 ; diseases of t<!cth. Ic8 ; 
diseases and dentistry of teeth. 1.39- 
162 ; swalhnvinir teeth, 1<)2, 193 y 
removal of fractured jaw, 197, 198. 

Bourgelat, Prof., milk molars, 69. 

Brandt, L.. length of incisors, 74 ; 
age of Spanish horses, crii)-biter* 
and mules, 215; age by shape of 
teeth, 215. 

Biewster. B, S , letter from, 292. 

Broadliead, G. C, account of fossit 
tooth, 112, 113. 

Broderip, Mr., a whale's tooth, 79. 

Burns, John, description by, 239. 

Butterfly, the, transformations of, 81. 

Cachalot, the, 79. 

Calcigeroup, origin of word, 18. 

C.ittlc, teething period of, 91,92. 

Came), the, teeth of, 06. 

Camper, P., temiiorary caninegi, 52. 

Canines, iern])orary, 51, 52. 

Calculus Concretions, 192. 193. 230. 

Caries, cau^e of, 14-1-154 : 165-173 ; 
svmptoms of. 118-154 ; dlff rent in 
dillerent teeth, 151 : odor of, 153; 
treatment of, ]51>-]71 ; treatment 
after treohniing sinuses for, 170 ; 
other dent il cases, 177-193 ; ccm- 
fonnded with glanders, 176, ISO, 
185; definition of, 231. 



280 



IXDEX. 



Cartwright, W. A., report of, 193 ; : 
tractiue of jawboue, 19ti. 

Cauc;K-ian Races, teerli oi\ 99. ! 

Cement, the, 9 ; size of tubes of, 16; 
use of, 17 ; mistaken for tartar, 17 ; 
vascularity of. 17 ; tninuess of, 17 ; 
color of, 18 ; resemblance to bone, 
23; germs of, 43; a proiecting 
varnisli, 53, GJ; microscopical cliar"- 
acter of, 133. 

Chabrit, M., tooth-germs, 274. 

Chalicoihcriidaj (fossil horses). 260. 

Chandler, C. F., on albumen, 227. 

C.iauvoau, A., harmony of teeth with 
genera! system, 11 ; development 
of tooth-germs, 41, 42 ; description 
of ircisors, 58. 59, 60 ; growth of 
teeth during life, 73. 

Cherry, W. A., shedding teeth, 59-1 ; 
judj;inz ago by shape of teeth, 204. 

Chcvfotain, 78 ; description of, 232. 

Claywortii, Surg., report of, 197. 

C )loman. Surgeon, discovery of, 116. 

' Columbus ' (elephant), tooth of, 275. 

Coluber Scaber (serpent). 121. 

Comparalive Anatomy, "iS?. 

Coni-ad, T., discovery of, 113. 

Complex grinders, cause of, 208. 

Concomitant Variation, a factor in 
evolution problem, 98. 

Condylarthra, the. 2'iO-l, 264. 

Cope, E. D., editor American Natur- 
alist, 113; physiological homolo- 
gies, 233; discovers Phenaccdus 
(teeth) and other fossil horses, 
S59-2G9 ; opinion of the Amblypo- 
da, 261-2. 

Copybara, the, srriudcrs of, 10; de- 
scription of, 283. 

Couehing and Teething, treatment ' 
for, 92. 

Crib-biting, effect of on teeth, 212- 
13 

Cumming, G., elephant tu^k, ^/IG. 

Cuvier, F , 16; noie on, 6'j ; bones 
and teeth of recent and fossil 
horses, 106; ophthahnic ganclion, 
221 ; elephant teeth, 275. 

Dana, Prof., geology, 940. 

Dandini, J., silver and golden hued I 

teoth, 25-6. 
D'Ai-boval. teething, 87. I 

Darwin, C. R., tushe ? of various ani- j 

mals, 77, 78, 79 ; changes in human i 

teeth, 99. 
Dawson, J. W., geologv, 243; mio- i 

cene period, 244 ; pliocene period, 

250. 
Day, E. C. H., narwhal. 246. 
Deciduous teeth, retention of, 129. 
Delafond, M., on trephining, 161. 
Denenbourg, P.. report of,"l3;3. 
Dental Cysts, importance of study ; 

of, 115; microscopical character of 



teeth in, 118 ; reports and theories 

on, 115-126. 
Dental Canal, the, 31, 224, 234. 
Dental i.'vscs, l!5-l:ib. 
Dental Nerve, the, 224-226. 
Dentinal, origin and use of word, 8. 
Dentinal Pulp, network of looped 

capillaries of the, 33-4. 
Deiumal Star, 59 ; description of, 

209. 
Dentinal Tubes, office and color of, 

22, 23 ; their two curvature^, 23 ; 

dichotomously branched, 131, 133 ; 

diameter of, 132 ; length of curves, 

133. 
Dentine, the, S, 14. 
Dentine Germ, 43, 59. 
Dentition Fever, 93. 
Dentition, permanent, 53-74. 
Dentition, temporary, 47-52. 
Dentition, third, cases of, 128. 
Digital reduction, cause of. 269. 
Dihoceras mirabilis (fossil), horns 

and canine teeth of, 236. 
Diverticula, use of, 22, 235. 
Doo- tooth-germs, grafting of, 27-8. 
Draper, J. W., obligation to, 4. 
Dugong, the, 79 ; description of, 235. 
Dunglison, R., development of teoth, 

45 ; diseases of teeth, 137 ; calculi, 

193 ; vocabulary, 227-256. 

Eddy, Dr., children's teeth, 277. 
E.iinburgh Veterinary College, re- 
port of, 179, 180. 
Editor Veterinarian, comments of, 

184; report; of, 201, 202. 
Elasmothere, the, great size of, 107; 

enamel festoons of molars of, 107 ; 

co'inecting link between horse and 

rhinoceros, 107. 
Elephant, great qunntity of cement 

in grinders of, 10 ; unique mode 

of cutting and shedding several 

dentitions; size, structJirc, &c., 

274-7; affinities with rodents, 260. 
Embrvo, human, transformations of, 

81-2 ; definition of, 236. 
Embryolosy, 80-82. 
Enamel, the, 10; tubes of, 18, 19; 

color of, 19; membranous sheaths 

of, 59; plications of, 106. 
Enamel, the two rings of, 59. 
Enamel-Fibers, direction of, 20; 

curves of, 20; form and size of, 20; 

diameter of, 134. 
Eocene (period) fossils of. 236. 
Equid?e. the, teeth of, 261. 
Evolution, doctrine of 77-9. 98-9.237; 

257-63 ; from inferior to superior, 

271 ; a bugbear, 271. 
Exostoses, 17, 116. 

Faenkel, discoveries of. 15. 
Falconio, Surg., di^icovery of, 118. 



INDEX. 



'ZSl 



Fersnii'on. P- ^ r development of i 
teeili. 45 j grinders. 6i ; ilie forma- 
tion of enamel, 04 ; giowlh of 
teetli during iile, IS; aiseaircs of 
teeth, lis ; Uis^ea.-es and dentisrtry 
of horses' leetii. Iyd-1G2; swallow- 
ing teeth, 1U2. 193. 

Filling children's teelh, 277. 

Fleming, G., dental cysts, 115-119; 
fractmed jaw, l'J5, li)G ; ou glan- 
ders, l".»y. 

Food, for foals, 5C; for tooth-cough, 
92 ; for uuc-qual weai" of grinders, 
143; alter trephining for caries, 
15), 102 ; for defective teeth, im- 
proving skin, fever, convalescence, 
&c.. lO.J-4; sifting of, 171: changes 
caused by, 272; bone-producing, 
277 ; sugar for horses, 3U. 

Forthonime. M., milk canines, 52. 

Fossil, cat-like animal, a. ZU. 

Fossil, definition of, 114. 

Fossil, hog-like elephant, v/ith tusks 
in both jaws. 241- 

Fossil Horses, cause of changes in 
teeth of. 268 ; do. reduction in 
toes of, 269. ^See Horses, fossil.) 

Fossil Horses, recent discoveries of, 
257-269. 

Fossil Tooth, a diseased, 173. 

Fractured Jaws, 194-202. 

Fnngns Haematodes, 173 ; definition 
of, 239. 

Gamgee, J., rojwrt of, 120-2. 

G.mglinn, nature of, 220-1, 239. 

Gurengeot. M., dental kev, l."36. 

Generali, Piof.. deniiil cysts, 116-19. 

Geology, definition of, 24J. 

Gill, T., nature of teeth, 12 ; d?ntuT 
forinnla for horse, 101 ; fossil hii ds' 
teeth, 114; teeth from diverticula 
(marsupials), 235; morphology, 
245; quadrumaua, 251, 252; lele- 
osts, 254. 

Girard, M., acre by marks and shape, 
206-7 ; dentinal star, 209.. 

Glanders, resembles caries of last 

frinders. 152-3; odor of, 1.53; may 
e caused by c tries of teeth (ab- 
porption of pus), KJO : sometimes 
imaginary, 170, 180, 1S5 : danger 
from and prevalence of. 199. 

Gomphosis (tooth-nrticulaiijn). 72. 

Goodsir, I*i-of., on tooth uenns, 125. 

Gonbaux, Surg., discoveiy of, IIT. 

Gowing, T. W.. on teeth. 171-72. 

Grice. C. C, report of, 12:3. 124. 

Grinders, tl'.e 5t ; tables of. 61 ; fig- 
ures formcci by. 61 ; contra>*ts 
between, 61, 62; their own whet- 
stones, (,0 ; mots of ('8,70; shed- 
ding of, 79. 71 ^activity of growth 
and undivided i)ase of, 74. 

Grouille, Mage, dental cy.«ts, 116. 



Guanaco, 78 ; description of, 240. 

Gubernaculum Deniis, the, descrip- 
tion of. 42. 

Gums, shrinkage of the, 72, 74, 172, 
181 ; atrect;'d l)y turgesceuce, 151 ; 
nerves of, 2'Za. 

Guilt, (Surg., ciisc'avery of, 117. 

Giitta-peicha as a lllling lor teeth 
and sinuses, 104, I7i; for children's 
teeth, 277. 

Haeckel, E. H., embryos. 81-2. 

Harris, Prof., 3d dentition, 129. 

Hartshorne, H.. evuluticm, 237. 

Ha^chischat ed dab, eflcct of on 
teeth, 25. 

Haw of the horse's eye (membraiia 
nictitans), description of, import- 
ance cf and evil caused by iguor- 
ar t grooms, 244. 

Hnyden, Lr., discoveries of, S57. 

Hayes, B.. tooth-pnlp, dentii.al 
tubes, cells and curves upon 
curves, cement, enamel, &c., 22-4 ; 
diseases of teeth. 137. 

Heard, J. M., obligation to, 216; 
letter fnmi, 292. 

Heath, J. P.. report of, 200. 201. 

Henoc(iue. M.. motor nerves, 217. 

Herbert, VV. 11.. age, 214, 215. 

He^^perornis (bhdT, teeth of, 114. 

Hespeiornis regalis, teeth of, 114. 

Hipparion. foss^il horse, 95, l;6. 111. 

Hippotherinm, fossil h( rj-e, 264-7. 

Hippotherium gracile. 2()8. 

Hippopotannis, canine teeth of, 63. 

Histoloirv, difiriticn of. 241. 

Hitchco\-k, C. H.. on fos^ls, 114. 

Hoeing, C. F., obligation to, 215 ; 
letter from, 292. 

H()<r, canine teeth of, 63. 

Hofsburgh, J., report of 175. 

Horse, significsftion of word, 274. 

Horse, the, theory of introduction 
into America, 110; a vegetarian, 
270; probably never carnivorous, 
272-3j once used for war only, 274. 

Horse Dentistrj', argument in favor 
of, 100 ; dental aiid other journals 
on. 287-292. 

Horse, genealogj of. 204. 

Horse, original home of, 273. 

Horses, fossil, A' acodon, 263 ; An- 
chippns, 80, 5.04; Anchitlicrium. 
96, 111, j12, 204; Anchitherium 
aureliauense, 2(5, 267; Anison- 
chns, 2(53; Chalicotheriidse. 200, 
264; EohippHs. (siijjposititions). 
259 ; "Equida', 2(')1 ; Equus cabalhs 
primigenias, 107; Equus compli- 
catus, 113; Equus curvidens, 107 ; 
Equus fossUis, 106; Kquus piici- 
dens. 107; Equus primiirenius, 107; 
Hipparion, k>6. 111, 112; Hippi- 
dium,268; Hippotherium^ 264r-7: 



282 



IKDEX. 



Hippotherium gracile, 268; Hyo- 
doaia, .-^iiii ; Hyoiiippa<, 11^; Hyra- 
cotlijriuiu, -^66, -ZM-); Lambdutiie- 
riuai, 'ii64:-i; Lopaiuaon aud Lo- 
phiodonddce, 2o8, 2M ; Meuisco- 
theriiun, Ji6J-4; Meryciiippus, 11:2 ; 
Mesohippus, J)?, 11;^, iio4; Orothe 
riuin, 2oJ ; Paleosyopous, 2'or, Fa- 
leotlieriidte, 261; raleoplotheiium, 
254; PeriptychLis, 263; Pliolophus, 
253-9; Protogonia, 26:3 ; Protohip- 
pius, 112, 2fil ; Systemodon, 259-64. 
(Sae confasioii ia nomenclature, 
pp. 253-9.) 

Hor.sei, fossil, 95-93, 106-13 ; extinc- 
tion of in SouTli America, 103 ; 
recent discoveries of, 25*7-263; 
early progenitors of (Amblypoda) 
possibly carnivorous, 272. 

Horse?, '•insane," 103. 

Horses without cars, 103. 

House, C. D., size of tooth-j?erms, 
31 ; on teething, 47-8 ; grinders, 
62; remnant teeth, 103, 104; re- 
moving a fractured tooth tbroup:h 
the nostril, 193, 199 ; operations 
in Worcester, Mass., 199; idle talk 
about glanders, 19 J; another prob- 
able mistake, 273 

Hudson, E. D., Jr., mucous mem- 
braae, 245 ; ovaries, 2i3. 

Hunter, J., theories of, 21-27 ; enam- 
el of grinders, 03 ; attachment of 
teeth, 72; use of canines, 83; su- 
pernumerary teeth, 123 ; pro\ing 
the formation of new dentine, 239. 

Hughes, J., dimensions of teeth, 49; 
periosteum of teeth. 137. 

Huxley, T. 11., ta;)ir, rhinoceros, and 
horse, 65-6; fossil horses, 110-11. 

Hyohippus, fossil horse, 112. 

Hyracotlierium, fossil horse, 258-64. 

Hyrax, teeth of and affinities with 
rhinoceros and elephant, 2!33. 

Iguanodon, the, molars of, 63. 

Incisors, the permauoat, 53 ; length 
of, 57; curvatures of, 57; Chau- 
veau's description of, 53-60 ; mi- 
croscopic character of, 130-135. 

Incisors, temnorary, 47-52. 

Inferior Maxillary Nerve, the, 223-24. 

Jacobs, W., on elephant. 275. 
Jaw, djscription of lower, 62. 
Jaw Movements, changes in, 233. 
Jaws, fractures of the, 94-232. 
Jaws, hnman, c'lau'res in, 53, 90-100. 
Jennings, R , rem laat tooth-germs 
and remnant leeth, 104. 

Knowl^on, J. C, bisho-Ding, 211. 
Koch, Robert, di-^covery of, 255. 
KOlliker, Prof. Rudolf Albrecht. on 
tooth-germs, 33, 43, 43, 274. 



LvFossB, Prof., dental cyst?, 120. 

Lambdotherium. fossil horse, 234-7. 

Lampas, cause of, 88-91 ; lancing 
recommended lor, 87, 91 ; buruuig 
for disapproved, 90-1. 

Lancelet, tiie, comparison to, 81. 

Lanzillotti Buonsanii, Prof., on den- 
tal cysts, 115-18. 

Lecoq, Prof., canine follicles, 44 ; 
temporary canines, 52; descrip- 
tion of grinders, 69-71 ; do. ca- 
nines, 76-7 ; remnant teeth, 100. 

Leeuweuhoek, discoveries of, 13. 

Legros, C, experiments of, 2i'. 

LeJdy, J., letter from, 101 ; fossil 
teeth, 113; 257, 259; opinion of, 
273. 

Lincoln, A., 211. 

Lion, the, canine teeth of, 83. 

Liquor Sanguinis, the. 22, 242. 

Lophiodon, teeth of, 258, 260. 

Lubin, R., discovery of, 127. 

Lyell, Mr., N. American fossil tooth 
corresponding to S. Amer., 110. 

Macrops, Surg., experiences of, 117. 

Madder, effect of on teeth, 24. 

Magitot, E., 27; development of 
tooth-germs, .human fetus, 46. 

Malpighi, discoveries of, 13. 

Mau, "canine leeth of, 82, 83. 

Man, early progenitors of, 80-3. 

Manteodon, prophecy tooth of, 262. 

Marks, dimensions of, 57. 53; two- 
fold use of, 204 ; too much cement 
in, 209, 210. 

Marsh, "O. C. evolution of horse, 95- 
98; no 'mark' in teeth of early 
forms, 203; fossil birds' teetli, 
114 ; description of mastodon and 
megatherium, 243; the Lophio- 
dons, 253 ; Orohippus, 259. 

Mastodon, the, 109, 114, 243. 

May C, report of. 178, 1V9. 

Mavhew, E, the comeut, 17, 18 ; 
judging age by teeth, 237-3. 

Mayo, Mr., experiments of, 218. 

Megatherium, the, teeth of, 107, 108 ; 
description of, 243. 

Melanian Races, teeth of. 99. 

Membraua Nictitans, in early pro- 
genitors of man (Darwin), C2 ; 
nerve for in horse, 222 ; descrip- 
tion of, 244. 

Meniscotherinm, fossil horse, 2G3-4. 

IMerj^chippu^, fossil horse, 112. 

Mesohippus, fossil horse, 97, 112. 

Miocene (period) fossils of, 244. 

Miohipuus. fo'^sil horse, 112. 

Molars' bunodont, 263. 

Mol irs. seleno-lont, 263. 

Molars, the, 54 ; ineliuation of, 54 ; 
description of, 09-71 ; microscop. 
ical character of. 130-35. 

MoonBliiidncss, cause of, 105. 



IXDEX. 



283 



Mooro, T., a mountain herb, 23, 
Morpliologv. definition of, 24;5. 
Morion, Prof., treatis^eby, 193. 
JMules' Toeili, tt'Uiug age by, 215. 
Miiller, Prof., discovery of,' lJ-5. 
Munljac-Deer. 78, 240. 
Mutfk-Doer, TS, 24.-). 
Mylodon, tUe, 1U8, 246. 

Narwhal, the, tushes of, 79 ; de- 

t^cripiion of, 240. 
Natuiv biin-icaJiug disease, 139, 209. 
Newberry, J. S., zoOlogy, 256. 
Niebuhr, opinion of, 25. 
JSippers, the, use of word, 47. 
Nomenclature, confusion in, 2^-9. 

Odontoblasts, the, 31. 

O Inntolithos, tlie. 17, 217. 

Odanturnithes (binls), teeth of, 114. 

Odoutonecrosis, 138. 

Olontryuv, operation of, 13S. 

Ohlinger, O. P.. discovcrv of. 113. 

Ophthahnic Nerve, the, 219-22. 

Ornithorhynchus, the, 80, 247. 

Operating, rules for, 154-lGO. 

Oreste, Surg., discovery of, 118. 

Orohippu^, fossil horse, teeth of, 96, 
large tushes of, 97; toes of, 97; 
size of animal, 112; name of, 259. 

Osteo-sarcoma, case of, 186. 

Owen, R., dental sciencL\ 8, 10, 13- 
22; tooth-gerins. 32-37; breadth 
and thickness, 49 ; temporary ca- 
nines, 51 ; teething, 55 ; descrip- 
tion of grinders, 64-GS ; teeth of 
anoplothcre. 65 ; do. ruminants, 
05 ; do. tapir. 65 ; do. rhinoceros, 
6 ; do. mc-gat'-ierium, 107; rem- 
nant teeth, 102 ; fossil horses' 
teeth, 103-10 1 ; microscopical ap- 
pearance of horses' teeth, 130-135; 
diseases of teeth, 131'; diseased 
fossil tooth, 173, 174; the fifth 
pair of nerves, 225, 221 ; discovers 
Hyracotherium, 2.58 : teeth of ele- 
phant, 275, tooth-va'^eularity, 20; 
probable circulation and proionsra- I 
tiou of nerves in dentinal tubes, 30. 

Paleoxtologt. definition of, 248. 

Paleosyopous, fossil horse, 267. 

Paleothere, teeth of. GS. 

Paleotheriidse, fossil horses, 261. 

Parker, Willavd, on caric-, 2"1. 

Parnell, C, remnant teeth, 102. 

Parrot-Month, 1'57. 1C8. 

Patholo','y of the Teeth, 130-174. 

Perciva'l, W.. teething, 83-81 ; lam- 
pa^, 8^-90 ; di>^ea«es of teeth, 1.08, 
135: onhtbalmip ganglion. ?21. 

Perio-teu'.n. ela'^ticity of, 7i ,74 ; def- 
inition of, 240-.5*. 

PeriptvchuP, a fossil horse with teeth 
resembling a serpent's, 263. 



Perisf-odactyla (odd-toed mammals), 
2.;7-(i4. 

Pessina, Prof,, discovery of. 215. 

Phenacodus (earliest lossil horse), 
description of, 200-;i<H. 

Pierce, l)r., opinion of, 287. 

Plassc, M., mouth-screw 150. 

Pliocene iperiod), fossils of, 250. 

Piiohippus, fossil horse, size oi, 112; 
confusion in name of, 259. 

Pliolophus, fossil horse, 2.58 9. 

Pony, great suffering of a, 201, 

Portal, learning of, 14. 

Ponchet, M., tooth-trerms, 274. 

Premolar, rea-^ons for use of word, 
53; inclination of the, 54. 

Processes, alveolar, diseases of, 166. 

Protogonia, fossil horse, 2G3. 

Proiohipous, fossil horse, 112. 264. 

Public Opinion, 287-92. 

Pidp, the tooth, 31. 

Pulpal Cavity, relation of, 22. 

Purkinjj, discoveries of, 14, 16; cor- 
puscles of, 9 ; cells of, 10. 

QUADRUMANA, the, 36, 81, 251. 
Qiiain, Jonas, fifth nerve and oph- 
thalmic ganglion, 220. 

TlAMSEY, J.jSkillof, 104. 

K-i'iux. C, obligation to, 28. 

Renault, Robt., report of, 187-92. 

Regimen, 102-104. 

Retzius, Prof, discoveries and con- 
jectures of, 10. 19 20, 21. 

Revel, M., report or. 1(^7. 

Reversion, doctrine of, sQ. 

Rhinoceros, the, teeth of, 67. 

Rhinoceros, the v.'Oollv, £51. 

Rich, Dr.. children's teeth, 277. 

Riders, first nations of, 273. 

Ri'i-ot, temi)orary canines, 52. 

Robin, C, doir tooth-serms, 27. 

Rockwell, E. A., report of. 277. 

Rodet, Surireon, on dental cysts. 118. 

Roiidanoosky, M., on nerves, 218. 

Rousseau. M'., cutting milk teeth, 48. 

Rmninants, teeth of, 65; four stom- 
achs of, 252. t 

Ruini, discovery of, 09. 

Ryder, J. A., treatise of, 268. 

Santt. a. H., report of, 180. 
Satterthwaiie, T. E., on corpuscles, 

233-4: on tubercles, 2.55. 
Sc 'rulothero, remains of. 108. 
Scliaaffhau en shortened jaws, 99. 
Sc'nvanu, Dr.. researches of. 20. 
S ^elve Prof., correlation forces, 234. 
Seleetion, natural, 98. 
Selection, sex'ial, 98. 
Sewell, \y.. ^"ental rysts. 122. 
Shark, fossil, teetli of, 230. 
Simonds, Prof., lever-forceps, 156. 
Sinuses, valves, osseous plates, &c., 



284 



INDEX. 



of, 153; gutta-percha as a filling for, 

177. 
Smith, W., report of, 182-184. 
Speculum Oris, u^e of, l-!9. 
Spencer H.. evoiuiion, 237. 
Star, dentinal, 59, 209. 
Stone, c-ise of in horse's jaw, 193. 
Strong, Di"., translation by, 2T4. 
Superior Maxillary Nerve, the, 222. 
Su!)ernumerary Teet^i, 127-12J ; 139. 
Surraou, II., report of, 17 i". 
Shallowing a Di^ea-ed Tooth, death 

of a hors.j from, 187 19.2. 
Swallowing a heathy tooth, 193. 
Systemoddn, fossil horse, 259, 263-4. 

Tables of Grinders, the, Gl. 

Teeth, abnormal, cases of beneath 
right kidney and near right ear of 
a lamb, llli-17; on mastoid process 
of temporal bone, posterior part of 
sphenoid bone and in testicle, 117; 
in ovaries, orbit, palate, tongue, 
side of jaw, cheek and neck, 119; 
base of ear, 124. 

Teeth, absorption roots of, 48, 70-1, 
27r>-!j, 28S. 

Teeth, cat'ine (horses'), description 
and probable extinction of, 75-77. 

Teeth, canine, use of in difterent an- 
imals, 77-83 ; made to tear flesh, 
271. 

Teeth, constant in the same type, 
and generally appreciably modified 
according to famil.y, 12. 

Teeth, continuous growth of, 73, 
143 ; extraction on account of. 
178. 

Teeth, deciduous, retention of, 129. 

Teeth, elephant, uaiqne mode of 
cutting and shedding several den- 
titions, 274-5 ; size, structure, &c., 
274-6 ; great quantity cement in. 10. 

Teeth, elephant (Indian), indications 
of age by, 275. 

Teetli emanating from osseous sys- 
tem, 131. 

Teeth, foals', absorption of roots of, 
non-continuous growth of, scarci- 
ty of cement on crowns of, 43 ; 
crowns worn off by attrition rath- 
er than shed, 50 ; breadth of, 49. 

Teeth, fossil birds', 114. 

Teeth, fossil elephant, weight of, 276. 

Teeth, f)ssil horses' (see '• Horses, 
fossil," p. 281"). . 

Teeth, fossil horses' (South and N. 
American), 103-10. 

Teeth, goa's', gold and silver hues 
produced iu. 25-6. 

Teeth, growintr. effect of madder on, 
white red and whit", 25. 

Teeth, horses', anomalous condition 
of, 142, 

Teeth, horses', dimensions of, 71. 



Teeth, horses', discovery that they 
indicate age. 215. 

Teech, horses', fillings for, 164. 

Teeth, horses', signs of improve- 
ment in, 266, 271. 

Teeth, horses (.Spanish), peculiari- 
ties of, 215. 

Teeth, hoises', temporary, 47-52 ; 
permanent, .53-74; canines, 75-63; 
remnant, 94-114 : abnormal. 115- 
127 ; supernumerary, 139 ; under 
the microscope, 1S6-1E5 ; pathol- 
ogy of. 136-174 ; dentistry of, 175- 
193 ; indicators of age. £.03-215. 

Teeth, human, changes in, 99. 

Teeth, in harmony with general sys- 
tem, 11. 

Teeth, nudes', telling age by (differ- 
ing somewhat from lunse), 215. 

Teeth, readily preserved in a fossil 
state, 12. 

Teeth, remnant, 94; regarded as 
phenomcnons, 94, 101 ; line of de- 
scent, 94; not to be conlouuded 
with su'^ernumeiaiy teclh, 94 ; 
the name. 94 ; easily lo.'-t. 99-iOO. 

Teeth, rudimentary, 99; why good 
teachers, 99. 

Teeth, uipt rnumerary. 127-8, 139. 

Teeth, three sets of, 128. 

Teeth, transplanting of. 26-29. 

Teeth, tubes (hollow columns) of, 12. 

Teeth, value of to the ai.atomist, 11. 

Teeth, variety and use of, 10. 11. 

Teeth, various animals', Boar, 77, 
84; Cachalot, 79; Camel, 6C. 78; 
Cattle, 91-2 ; Chcvrotain. 78. 232 ; 
Coluber Scaber, 121 ; Copyhara 
(or Ca-ybara). 10, i:.33; Dinoceras 
mirabilis (fossil) 236 : Diigong, 19, 
235 ; Elephant, 77, 274 ; do. fossjl, 

244 ; Hippopotamus. 63 ; Hog, 63 ; 
Hyrax, 200; Igranodon, 63 ; Lion, 
83 ; Mast(-don. 109, £43 ; -JMegathe- 
rium, 107. 243; Muntjac deer, 78, 

245 ; Musk-deer, 78, 245 ; Karw hal, 
79, 246 ; Ornithorhynchns, SO, 247 ; 
Bhinoceros, 67 ; JRuminants, C5, 
252 ; Shark (fossil), 236 ; Tapir, 
65; Toxodon, 109, 254; Walrus, 
77 ; Zebra, 52. 

Teeth, vascidarity of, 22-30; nerves 
and circulating vessels of, 26. 

I'eeth, wolf, why called remnant, 94. 

Tenon, verities Ruini's discovery, 69. 

Tennyson's " gulf cf doubt," 270. 

Toes, 97, 112, 265 ; cause of reduction 
in number. 269 ; form a semicircle 
when applied to Ihe ground, ;v69. 

Tomes, C. S., tooth-germs, 37-41 ; 
temporary canines, £2 ; dentine, 
enamel, and cement, 63; attadi- 
ment of teet";, 72 ; tushes < f boars, 
84-5 ; evolution, 98-9 : no • mark ' 
in teeth of early fossil horses, 203. 



INDEX. 



285 



Tomes, J., a tooth barricading dis- 

ea.-e, 139. 
Tooili, abnormal, description of, 123. 
ToOlIi. a disv-asei lossii, r.3-4. 
•loom, a trac.ured, 19S-y. 
Tooth, a propuccy. -^o-i. 
Tootii. a whalef, (lc^^cription of, 79. 
Tooth, t'lepbaut, m W onli's Aluseum 

(New York), ::iT5. 
Tooili ill upper jaw of a bull, 127. 
Toolh, iiaiui-e ol, 7, 8 ; iridescence 

of. 12, IG; no inherent power of 

reparation in, 137. 
Tooth i^ulp. description of, 31. 
Tooth, roiunaut, vicious inclination 

cf a, 104. 
T(y)th, swallowing a diseased (fatal), 

Tooth, ewa'ilowing a healthy, 193. 
Tooth-Cough, treatment for. 9:1. 
Tooth-Germs, developuient of, 31-46. 
Tootli-Ger.-is, ( Ois'. graltiug whole 

term's, Reparaic enamel organs, 
entine cays, &c.. in dogs and 
guinea-pi^?, tho.-c in the latter 
anim'il failing, 27-S. 

Tootii-Germs, elephant, Z7i. 

Tooth Germs, human, transforma- 
tions of cjiithelial and enamel 
geriiis, dentine bulbs, caps, &c., 
in, fro!!i 7th to 39th week, 46. 

Tooth-Tumor, nnusnal ca^e of, 196. 

Tooth and Bnne. analogy of, 23. 

Toxodon, remains of, 109 ; descrip- 
tion of, 2.j4. 

Trepiiino, the. 254. 

Trephining Sinuses, 157-161. 

Trigeminus Nerve (in the horse), de- 
scription of, 21(^226. 

Tripier, M.. resection of nerves, 217. 

Trucar, the, 25.5. 

Tushes, fighting with, in various 
animals,'77-85. 

Tu-he^ horses', practically useless, 
75; difForent from other teeth. 75: 
distances from incisors and grind- 
ers, 75, 71 ; shape and dimensions 
of, 76; curvature of roots, 76. 

Tushes, removal of, 1.55. 

Tushes, size of in Orohippus, 97. 

Tusks, elephant fighting with, 77 ; 
varying curvatures, weight, length, 
&c., of. 276. 

Tuttie, R. M., on evolution, 270-2. 

Vabnbll, G., opinion of, 102 ; dis- 



eases of teeth, 1.3S. 13^; ; the sinuses, 
15.J. loJ. llil ; canes, 164-10(3; uit- 
cases of aivcoiar processes, luu; 
parrot-mouth, 16T; osteo-sarcoma, 
186-7; Iractui-ed jaws, 194. 
Views of an cvoiuiumist, 270-2. 

Wallace- A. R., cause of destruc- 
tion of ungalaia. Ill; fossil horses, 
112 ; theology, 2-10. 

Walrus', tlie, mode of fighting of, 77. 

Walsh. J. II., age by teelii, :to8. 

\\ edges, scientific, use of. 271. 

West, bone-beds of the, 257. 

Wheeler, Capt., report on survey of, 
261-2. 

Williams, Prof. W., teething, 91 ; 
remnant teeth, 104, 105 ; dental 
cysts, 125-127 ; caries. 1(.9-171. 

WiiliauiS. W., nccrosit:. 2J6. 

Winter, J. H.. use of tushes, 85. 

Wolf-tcelh, why a good generic 
name, 91. 

Woodward, J. J., tooth pulp, 31 ; 
histology. 241. 

Woolly Rhinoceros, (fossil), 251. 

Wor4:s, general, 4. 

Works, special, 4, 290. 

Wort man. J. L.. on fossil horses, 
2,57-i69; discovery of. 260. 

Wyman, Prof, discovery of, 81. 

Yates, L. G., fossil elephant teeth, 
276. 

Youatt, W.. susrar as food. 30 ; 
tooth-germs. 44, 45 ; infundibula 
of grinders. 58; description of 
lower jaw, 62 : use of tushes, 84 ; 
teething, 85, 86 ; lampas, 90, 91 ; 
cropping horses' ears. 103; rem- 
nant teeth, 105; food, 1C2-1G4 ; 
disease's of teeth. 172, 173 ; frac- 
tured jaws. 196-198; 'mark' of 
central nippers, 205; difficulties 
of judging age, 20'?: bishoping, 
210"; tnd- tricks. 212, 214 ; crib- 
biting. 212, 213 ; indications of a?e 
inr'ependent of teeth. 214 ; fifth 
])air of nerves, 216-225; cneoum, 
2.30; colon. 2.32; mcrnbrana nicti- 
tans. 244 : solipeds 253. 

Youmans, E. L., evolution, 237. 

Zebra, temporary canine teeth of, 

.52. 
Zoology, definition of. 256. 



PUBLIC OPINION. 



Horses' Teeth. — Such is the title of a work we have just 
read with considerable interest, because it embraces much that 
is instructive and useful. Designed as the publication is to 
give a synopsis of the fundamental principles of dental science, 
it has a defect attributable to the author's lack of practical 
experiencs in the specialty of which he treats. * * * The 
chapter on canine teeth contains much of interest, and fully 
sustains the theory that horses sutFer from febrile irritations, 
as the result of interrupted dentition, and that the free use of 
the lance is as serviceable as when used on an obstructed eye- 
tooth of a child. The disease known as lampas, which is often 
accompained by a distressing coucrh, and which so seriously 
interferes with feeding, is shown to be due to the same cause 
and to require the same remedy. To state that caries most 
frequently proceeds from inflammation beginning in the pulp- 
cavity, or that caries of the roots is the result of inflammation 
of the alveolo-dental periosteum, is certainly far from the ex- 
perience of the practical dentist; but, notwithstanding- these 
defects, there is much of value in this (the eighth chapter) as 
well as the succeeding chapters on the dentistry of the teeth, 
their indications of age, their nerves, &c. * ^ *, — C. N. 
Pierce in "Dental Cosmos." 

"Horses' Teeth," by Wm. H. Clarke of New York, is a 
neat and handsomely bound volume, containing selections from 
the very best authors, with appropriate additions by the 
author, making' a book that is invaluable to veterinary sur- 
geons, and of great practical benefit to dentists, and should be 



288 PUBLIC OPIis^IOX. 

studied by every parson wlio treats the tectli. The nuthor 
treats of the teeth from the time of the formation of the germ 
to their full development, and gives their pathology and den- 
tistry also. A vocabulary of the technical terms used forms a 
valuable addition. — Dental News. 

This work is undoubtedly in advance of anything hereto- 
fore published on the subject in this country. " * * When 
the author says that " probably the temporary teeth are 
absorbed by the permanent," he displays the folly of attemi^t- 
iiig to write on a subject that one does not understand.* Still 
the work is useful and will probably aid in the elevation of 
veterinary surgery. — Missouri Dzntal Journal. 

This book is in a great measure a compilation from works 
on dentistry, anatomy, physiology, microscopy and veterinary 
surgery, as they relate to the davelopment, structure and care 
of the teeth of horses. As we are a believer in horse dentistry, 
we have looked over the work with much pleasure and no 
inconsiderable profit. — Dsmal Advertiser. 

This book is a venture in the field of veterinary science 
which we hope to see more frequently imitated. It is mainly 
a compilation, admirably arranged, and prepared with great 
thoroughness of detail. The compiled matter is well selected 
and condensed, much of it being rewritten. It contains much 
besides the matter pertaining to horses' teeth, the teeth of 
many other animals being described and compared with those 
of the horse ; in fact, the work might be entitled " Teeth " 
instead of •' Horses' Teeth." It gives a history of the evolu- 
tion of the horse from early geological periods, the wolf-teeth, 
which the author has named " Remnant Teeth," being traced 
back to the Eocene period, when they were functionally 
developed. This fact throws light on what has been a mys- 
tery, and the author appears to have made a discovery. 

The work, as a whole, is very commendable, and we feel 

* See pages 43 and 50. A few changes have been made and some fresh 
matter addeti. But I will venture to ask the editor of the Journal what 
becomes of the roots of a temporary tooth when the shell of its crown when 
shed is sometimes not more than the sixteenth of an inch in thickness? 
What becomes of the roots of elephant teeth ? (See pages 274-5-G.) 



PUBLIC OPINION. 289 

sure it will find a place in tlie library of all interested in a 
thoroughly practical as well as scientific knowledge of liorscs' 
teeth, and will be found especially valuable both to the student 
and practitioner of comparative medicine and surgery. — Jour- 
nal of Comparative Medicine and Surgery. 

The work consists mainly of quotations from standard 
writers. It is very interesting and instructive reading, and is 
fully worth the small sum it costs. The author deserves credit 
for his labor in collecting information from so many separate 
sources, and presenting it in so small a compass and so readable 
a form. However, there are errors in the vocabulary that ought 
to be corrected. — Veterinary Oazette. 

It possesses the merit of presenting in a condensed form, for 
the study of the veterinary surgeon, the anatomy, pathology, 
and reparative surgery of horses' teeth, and to him it will save 
much labor and furnish a ready reference, and hence be an 
eflScient aid. * * * — Medical Gazette. 

* * * The work contains an immense amount of useful 
information, and as it fills an unoccupied field, ought to be 
successful. — Medical Record. 

We understand this book is having a rapid sale among 
horsemen. Hereafter we suppose the title H. D. D. will be- 
come common. How nicely Mr. Clarke tells us of the cutting 
and shedding of the temporary and permanent dentitions. In 
the future we expect that greater attention will be given to the 
iQeih..— North American Journal of Homeopathy. 

Horses' Teeth. — Owners of all classes of horses should be 
in possession of a remarkably useful work entitled " Horses' 
Teeth," by Wm. H. Clarke. The w^ork is based on the best 
authorities on odontology and veterinary science, and arranged 
in an easy, comprehensive form. With a view of rendering 
technical tenns readily understood, a vocabulary of the medical 
and technical terms is attached. Dental science, as hitherto 
expounded, has never afforded horse owners the instruction it 
professes to aim fit. The trouble has been the use of technical 
phrases. Mr. Clarke, alive to the necessity of giving to the 
public a popular treatise, has presented a work which must 



290 PUBLIC opi:n"iok. 

find its way in all circles, and, above all, reach the understand- 
ing of the average reader. — Turf, Field and Farm. 

This work deals with horses' teeth in a very complete man- 
ner, and will doubtless be found of great value by students of 
veterinary science. It is a compilation, but Mr. Clarke has done 
his work in a careful manner. * * * A study of this work 
cannot fail to be of value to all who are interested in the 
horse. — London {Eng.) Live Stock Journal. 

The book is compiled from the best authorities. — Rural 
New Yorker. 

Horses' Teeth. — We have received from Mr. W. H. Clarke 
a duodecimo volume containing a compilation of everything 
valuable thiit has been written by the best known odontologists. 
* -H- * The so-called " wolf-teeth " are traced to the horse 
which existed previous to the pliocene period. Mr. Clarke 
calls them "remnant " teeth. * * * The work is a valuable 
addition to veterinary science.— T/ie Country Gentleman. 

It is a venture in the field of veterinary science, and, though 
in general a CDmpilation, will be found of great practical service, 
and in its present form a new thing. It will be of use especially 
to horsemen and fanners. — Massachusetts Ploughman. 

This work is mainly compiled, but the selections evince care, 
judgment, research, and discrimination. It will prove valuable 
to the veterinary student and practitioner. — Pen and Plow. 

Had this work been issued prior to Huxley's " Crayfish " or 
Comte's '' Sight " it would have been deemed too special. The 
subject is scientifically treated, with a decided tendency toward 
the practical. * * *. — Syracuse Standard. 

Horses' Teeth. — * * * Mr. Clarke devotes considerable 
space to descriptions of the different classes of teeth. * « * 
Although there is a ^reat deal of technical language in the 
work the copious vocabulary at its close renders it practical for 
those who wish to learn about the structure and diseases of the 
teeth, and the method of treating them under various circum- 
stances. Many instances are quoted from good authorities in 
which horses have been treated for diseases of the jaw, and the 



PUBLIC OPINIOX. 291 

metliods by means of wliich they were cured are carefully set 
forth. We present some extracts from the chapter on the teeth 
as indicators of age. (See pp. 204-5.) The treatment of this 
subject is only an example of the fullness and accuracy of the 
entire work.— Utica Herald, 

Mr. W. H. Clarke's " Horses' Teeth " is a complete and 
interesting treatise which may be accepted at once as both a 
useful manual of equine dentistry and an agreeable study of 
certain aspects of comparative zoology. Every possible de- 
formity or peculiarity observable in the teeth of the horse, as 
well as every roguery practiced on them by dishonest dealers 
is fully handled, and a succinct account is given of all the 
maladies of the teeth themselves, and of other organs with 
which the teeth have a functional relation. — New York Herald. 

The treatise on horses' teeth by William H. Clarke, a metro- 
politan journalist, has already attracted wide attention, and is 
an invaluable work in its way. Great care and much labor 
have b3en bestowed in its preparation, and the book supplies a 
want that has long been felt by horsemen, farmers and the 
student and practitioner of comparative medicine and surgery. 
— New York Graphic. 

The title so fully describes the scope of the volume that 
little need be added except criticism. The author is frank 
enough to admit professional inexperience, but has made the 
topic of the work a matter of careful investigation for a year. 
He has wisely deferred to the opinions of naturalists and veter- 
inary surgeons, and quotes liberally from their works in every 
chapter, thus supplying a cyclopedic stock of information bear- 
ing directly on horses' teeth in health and disease, which is 
very convenient for those who keep or raise horses, and the 
average veterinary surgeon. — Phrenological Joicrtial. 

The thoroughness of detail with which every point relating 
to the subject of this work is treated will im[)ress every one 
with its reliability and value. It is undoubtedly true that 
much suflfering, disease and death have resulted from ignor- 
ance of what Ts herein given, and that much unintentional 
cruelty to horses may be prevented by studying this volwne. 



292 PUBLIC opiKiON^. 

Thoagli the title implies tliat the work is confined exclusively 
to the teeth of horses, it is not so ; the teeth of other animals 
claim nearly as much attention as those of the horse. The 
theoiy of evolution is introduced, the history of the horse being 
traced from the Eocene period, when the wolf or "remnant" 
teeth were functionally developed. The hook will be prized by 
all who seek the welfare and happiness not only of the human 
race, but of all sentient beings. — Banner of Light. 

We all know that horses suifer with their teeth, and the 
work gives full instructions as to their care. * * * The 
author is an evolutionist, and has devoted much study to fossil 
horses. — New Orleans Times. 

Practical Books. — " Horses' Teeth," is a valuable treatise 
that ought to be in the possession of horsemen, farmers, and 
veterinarians. * * *. — Pittsburg Commercial Gazette. 

Dr. C. F. Hoeing (Jersey City Hights, N. J.) says : " After 
a careful reading of yoar book, * Horses' Teeth,' I wish to say 
that it appears to me to be an able compilation of scientific 
fa:;ts, and a basis for further investigation of horse dentistry 
by the profession; at the same time containing valuable in- 
formation for intelligent horsemen and farmers, as well as 
naturalists generally. I miss only very valuable information 
to be found in numerous German books." 

Dr. J. M. Heard, 205 Lexington Ave., New York, says : 
" The book is full of valuable information ; in fact, one would 
search a single library in vain to obtain it. None bat those 
who have performed similar work can appreciate the immense 
amount of labor expended in its j)reparation. No student or 
practitioner can afford to be without it." 

Dr. B S. Brewster of Norwich, Conn., says : " I have been 
an advocate of horse dentistry for thirty years, even arguing 
against veterinary surgeons. Thank God, light has come at 
last." 




l-Year-Old, Lower Jaw {Brandt). 




2- Year-Old, Lower Jaw ; drawn from Nature. 




3 Year-Old. Lower Jaw; drawn from Nature. 




II 11 

4- Year-Old, Lower Jaw ; drawn from Nature. 




5-Year-Old, Lower Jaw ; drawn from Nature. 




liifc 

6-Year-Old, Lower Jaw ; di-awn from Nature. 




7-Year-Old, Lower Jaw (Brandt). 




8-Year-Old, Upper Jaw (Walsh). About H nat. size. 




9-Tear-Old, Upper Jaw (Walsh). About % nat. size. 




10- Year-Old, Upper Jaw (Wal^h). About % nat. size. 




11 years, Upper Jaw. The marks have disappeared. 





The Mark, dissected as it 
were. (See page 58.) 



c, The Dentinal star, some* 
times mistaken for the 
mark. (See page 209.) 




li« 



12 years. Lower Jaw. Change in shape is now clearly defined. 
The respective pairs (centrals, dividers, corners) assume in turn 
(from 12 years till old age) various shapes— semi-square, rounded, 
triangular, wedge-shaped, etc. 




13 years, Lower Jaw. 




14 years, Lower Jaw. 




15 years, Upper Jaw. 




16 years, Upper Jaw, 




■» >.vC\vCvv»>'>"^^ 



17 years, Upper Jaw. 




18 years, Lower Jaw. 




19 years, Lower Jaw 




20 years, Lower Jaw. 




21 years, Upper Jaw. 







22 years, Upper Jaw. 




23 years, Upper Jaw. 




24 years, Lower Jaw. 







25 years, Lower Jaw. 




26 years, Lower Jaw. 





28 years, Upper Jaw. 




29 years, Upper Jaw, 




v:i I 



% f" w 



i'liiim 



A Parrot-Moath (lower jaw). The ten lines represent ten 
years' growth. The marks, having never been worn, represent 
a 6-Tear-old. The horse is therefore 16 years old. (This cut, 
as well a» many of the preceding, is from Brandt's "Age of 
Horses.") 



5obn IRe^nbets a Ca, 




MANUFACTURERS AND IMPORTERS OF 
OF SUPERIOR QUALITY AND WORKMANSHIP. 

Slings for Suspcnbing Hntmals 

A SPEC I ALTY. 

mo. 303 ffourtb H\>enue, 

Hem IJorf. 



Price List of Veterinary Dental Instruments 
Illustrated in this book. 

Plate I. Fig. 1. Adjustable Tooth File ; in handle to unscrew, $4.00 

" " 2. " " " in stiff handle 3.00 

House's " " in handle to unscrew, 4.00* 

House's " " in stiff handle 3,00* 

" 3. Prof, Going's Tooth Chisel 17.50 

" 4. FrcnchModel " " 14,00 

•' •* 5. Tooth MaUet. lead filled, not rebounding 2.50 

" " 6. French Model Tooth Saw 3.50 

•* " 7. Narrow Tooth Chisel, length 5 inches 1.25 



Plate I, rig. 8. Narrow Tooth Gouge, length 5 Inches $1.50 

" " 9. Tooth Easp guarded ; in stiff handle 3.00* 

•* " " in handle to unsprew.... 3.75* 

" plain ; in stiff handle 1.75* 

" " plain ; in handle to unscrew 2.50* 

«' •' 10. Extra Blade for Adjustable Tooth File 0.40 

Extra Blade for House's " " 0.40* 

Plate II. " 11. Heavy Tooth Forceps, length 15 inches 5.50 

" " 12, Prof. Going's Tooth Forceps with closing screw 

and crank handle 25.00 • 

" 13. House's Tooth Cutting Forceps, -j 

•• 14. House's Tooth Pulling Forceps, j. 28.00 

one set of removable handles to both j « 

" 15. Wolf Tooth Forceps, length 9 inches 3.50 

•• 16. Wide Tooth Chisel, length 10 inches 2.00 

*' 16 " 3.00 

Plate III. " 17. Tooth Cutting Forceps. French model 25.00 

"18. •« " " Holler's 32.00 

"19. •• " " French model 20.50 

" 20. House's Tooth Cutting Forceps 6.50 

"21. " " " " 6.50 

"22. " " " " 6.50 

"23. " " " " 6.50 

" " 24. Narrow Tooth Gouge, with steel head 2.00 

Plate IV. '• 25. Bow Tooth Saw. with two blades 6.00 

•• " 26. Tooth Key, with hooks of assorted sizes 35.00 

" 27. Plain Tooth Saw 1.50 

" " 28. Chain Tooth Saw 12.50 

" 29. Fine ferruled Tooth Saw 1.75 

•• " 30. Narrow Tooth Chisel, length G inches 1.25 

" 31. Hurlburt's Gum Knife and Tooth Pick 2.00 



Our Alphabetical Register of Veterinary In- 
stmments of 90 Pages and containing about 325 
engravings, mailed free upon receipt of four Cents 
fDr Postage, to all who mention this book. 




COLUMBIA VETERINARY COLLEGE 



SCHOOL OF COMPAPwATIVE MEDICINE, 



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THE 

REGULAR TERMS OPEN IN OCTOBER. 

Has the largest and best corps of Instructors of any Veter- 
inary College in the country. All its graduates in successful 
practice. For catalogue and further information apply to 

E. S. BATES, M. D., V. S., Dean. 



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